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 Mg 2SiO 4 (forsterite) is 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 coating having Mg 2SiO 4 as a main component on the surface, Ce is added to the primary coating in a basis weight of 0. It contains 001 to 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. In addition, 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 Ca, Sr, and Ba are insufficient in the raw material powder of the quenching separator, the development of the primary film will not be possible. Sufficient areas may be created and the adhesion of the primary coating may be reduced.
[0014]
An object of the present invention is a grain-oriented electrical steel sheet having excellent magnetic properties and excellent adhesion to a grain steel of a primary coating, a method for manufacturing grain-oriented electrical steel sheets, and annealing separation used for manufacturing grain-oriented electrical steel sheets. To provide the agent.
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. The number of Al oxides arranged within the range of 2.0 to 12.0 μm in the plate thickness direction from the surface of the primary coating and having a size of 0.2 μm or more with an area-based circle-equivalent diameter at the peak position of Al emission intensity. The density is 0.03 to 0.2 pieces / μm 2.
[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 8.0%, and the total content is 0.5 to 10.0%. 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 metal compound selected from the group consisting of Ti, Zr, and Hf in terms of oxide. The total number of Ti, Zr, and Hf atoms contained in the annealing separator is 2.0 to 14.0%, and the total number of Y, La, and Ce atoms is the sum of the total number of Ti, Zr, and Hf atoms. The ratio is 0.15 to 4.00, and further, it is a particle of a metal compound selected from the group consisting of Y, La, and Ce, and has a volume-based equivalent sphere diameter of 0.1 μm or more. The number density of the particles is 2 billion / g or more, and the particles are metal compounds selected from the group consisting of Ti, Zr, and Hf, and have a volume-based equivalent sphere diameter of 0.1 μm. The number density of the above particles 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 content of the metal compound in terms of oxide is 0.5 to 8.0%, and the total content of the metal compound selected from the group consisting of Ti, Zr, and Hf in terms of oxide is 0. It is 5 to 10.0%, and is selected from the group consisting of the total content of the metal compound selected from the group consisting of Y, La, and Ce in terms of oxide and the group consisting of Ti, Zr, and Hf. The total content of the metal compound in terms of oxide is 2.0 to 14.0%, and the total number of Ti, Zr, and Hf atoms contained in the quenching separator is further increased. , Y, La, Ce The ratio of the total number of atoms is 0.15 to 4.00, and further, it is a particle of a metal compound selected from the group consisting of Y, La, Ce, and has a volume. It is a metal compound particle selected from the group consisting of Ti, Zr, and Hf, which has a reference sphere-equivalent diameter and a particle density of 0.1 μm or more of 2 billion / g or more. The number density of particles having a diameter equivalent to a sphere on a volume basis and having a diameter 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 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 compounds, La compounds, and Ce compounds in a quenching separator. Study was carried out. 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. Further, the root of the primary coating becomes a factor that hinders the movement of the domain wall, and the magnetic 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 a Y compound, a La compound and a Ce compound 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.
[0024]
Therefore, the present inventors reduce the content of Y compound, La compound and Ce compound in the annealing separator mainly containing MgO, and contain Ti compound, Zr compound and Hf compound as alternatives to form a primary coating. Attempts to form these An attempt was made to increase the density of the number of particles of the compound in the annealed separator (raw material powder) before adjusting the number density 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 contents of the Y compound, La compound, and Ce compound in the MgO-based annealing separator and the contents of the Ti compound, Zr compound, and Hf compound to form the primary film. The root depth and dispersion were 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 Al peak position D Al is 2.0 to 12.0 μm and the Al oxide number density ND is 0.03 to 0.2 / μm 2, the primary coating It has been found that excellent magnetic properties and adhesion of the primary coating can be obtained because the roots have an appropriate length and an appropriate dispersed state.
[0027]
Al peak position D Al and Al oxide number density ND, as described above, the appropriate range is the content of Y, La, Ce compounds and the content of Ti, Zr, Hf compounds in the quenching separator and the annealing. The number density of particles of the metal compound selected from the group consisting of Y, La and Ce and the metal compound selected from the group consisting of Ti, Zr and Hf in the raw material powder before preparing the separating agent into an aqueous slurry. It can be obtained by adjusting the number density of the particles of the above to an appropriate range.
[0028]
Further, the total mass% C RE (described later) in terms of oxides of the Y, La, and Ce compounds when the MgO content in the MgO-based annealing separator was 100%, and the MgO content was 100%. An image showing the ratio of the total mass% C G4 (described later) in terms of oxides of Ti, Zr, and Hf compounds and the distribution of Al obtained by EDS analysis in the glow discharge scar region of Al peak position D Al. The number density of Al oxides in ND (pieces / μm 2) was investigated. As a result, the oxide-equivalent content of the metal compound selected from the group consisting of Y, La, and Ce and the oxide-equivalent conversion of the metal compound selected from the group consisting of Ti, Zr, and Hf in the quenching separator. It was found that the Al oxide number density ND can be controlled by adjusting the content of Al oxide.
[0029]
As a result of further studies, 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 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 8. It is 0%, and the total content of the metal compound selected from the group consisting of Ti, Zr, and Hf in terms of oxide is 0.5 to 10.0%, and the group consisting of Y, La, and Ce. The total of the oxide-equivalent total content of the metal compound selected from the above and the oxide-equivalent total content of the metal compound selected from the group consisting of Ti, Zr, and Hf is 2.0 to. The ratio is 14.0%, and 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 4. It is composed of the above Y, La, and Ce, which are 00 and have a number density of particles having a particle size of 0.1 μm or more in the raw material powder before adjusting the quenching separator into an aqueous slurry of 2 billion / g or more, respectively. By using a quenching separator to which the metal compound powder selected from the group and the metal compound powder selected from the group consisting of Ti, Zr, Hf are applied, the magnetic flux density improving elements (Sn, Sb, Bi, Te, Even if it is a directional electromagnetic steel sheet manufactured from a hot-rolled steel sheet containing Pb, etc.), the Al peak position D Al is 2.0 to 12.0 μm, and the area-based circle equivalent diameter is 0.2 μm or more. It was found that the number density ND of Al oxides of the same size was 0.03 to 0.2 / μm 2, and excellent magnetic properties and adhesion of the primary coating 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. Arranged within the range of 12.0 μm, the number density of Al oxides at the peak position of Al emission intensity is 0.03 to 0.2 / μm 2.
[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 separation agent contains 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 in terms of oxide of the metal compound selected from the group consisting of Y, La, and Ce. Is 0.5 to 8.0%, and the total content of the metal compound selected from the group consisting of Ti, Zr, and Hf in terms of oxide is 0.5 to 10.0%, and also. 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 metal compound selected from the group consisting of Ti, Zr, and Hf in terms of oxide. The total with the amount is 2.0 to 14.0%, and further, the total number of Ti, Zr, and Hf atoms contained in the quenching separator and the total number of Y, La, and Ce atoms. The ratio is 0.15 to 4.00, and further, the number density of the particles of the metal compound selected from the group consisting of Y, La, and Ce in the raw material powder before adjusting the quenching separator into the aqueous slurry. The number density of particles having a particle size of 0.1 μm or more in the raw material powder of the metal compound selected from the group consisting of Ti, Zr, and Hf is 2 billion / g or more, respectively. However, the particle size is the equivalent diameter of a sphere on a volume basis.
[0032]
The annealing separator further comprises one or more metal compounds selected from the group consisting of Ca, Sr and Ba, Ca, Sr, Ba atoms relative to the number of Mg atoms contained in the annealing separator. It may be contained in the range where the ratio of the total number of the atoms is less than 0.025.
[0033]
In the method for manufacturing grain-oriented electrical steel sheet, the chemical composition of the hot-rolled steel sheet is further 0.6% in total of one or more selected from the group consisting of Cu, Sb and Sn instead of a part of Fe. It may be contained below.
[0034]
In the method for manufacturing grain-oriented electrical steel sheet, the chemical composition of the hot-rolled steel sheet is further 0.03% in total of one or more selected from the group consisting of Bi, Te and Pb instead of a part of Fe. It may be contained below.
[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 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 8.0%, and the total content is 0.5 to 10.0%. 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 metal compound selected from the group consisting of Ti, Zr, and Hf in terms of oxide. The total number of Ti, Zr, and Hf atoms contained in the annealing separator is 2.0 to 14.0%, and the total number of Y, La, and Ce atoms is the sum of the total number of Ti, Zr, and Hf atoms. The ratio is 0.15 to 4.00, and further, in the raw material powder of the metal compound selected from the group consisting of Y, La, Ce in the raw material powder before adjusting the quenching separator into the aqueous slurry. The number density of particles having a particle size of 0.1 μm or more and the number density of particles having a particle size of 0.1 μm or more in the raw material powder of the metal compound selected from the group consisting of Ti, Zr, and Hf are 2 billion / g, respectively. That is all. However, the particle size is the equivalent diameter of a sphere on a volume basis.
[0036]
The annealing separator further comprises one or more metal compounds selected from the group consisting of Ca, Sr and Ba, Ca, Sr, Ba atoms relative to the number of Mg atoms contained in the annealing separator. It may be contained in the range where the ratio of the total number of the atoms is less than 0.025.
[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 the steel sheet composition 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 Si content is It is 4.0%, more preferably 3.8%.
[0042]
Mn: 0.02-0.2%
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 0.2%, secondary recrystallization does not occur and the magnetic properties of the steel deteriorate. Therefore, the Mn content is 0.02 to 0.2%. 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 base steel sheets 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 the secondary recrystallization and improving the magnetic flux density in the finish annealing, but if they remain in the base 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 Mg 2SiO 4 (forsterite). 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 is composed of at least one of metal compounds selected from the group consisting of Y, La and Ce, and Ti, Zr and Hf. Contains at least one of the metal compounds selected from the group. The total content of Y, La and Ce in the primary coating is 0.001 to 2.0% by mass. The total content of Ti, Zr and Hf in the primary coating is 0.0015 to 6.0% by mass.
[0051]
As described above, in the present invention, in the method for producing a directional electromagnetic steel plate, the metal compound selected from the group consisting of Y, La and Ce described above, and the metal selected from the group consisting of Ti, Zr and Hf are used. An annealing separator containing a compound is used. 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 the quenching separator contains a metal compound selected from the group consisting of Y, La, and Ce and a metal compound selected from the group consisting of Ti, Zr, and Hf, the primary coating also contains the above-mentioned content. Contains 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 content of Y, La, Ce and the total content of Ti, Zr, Hf 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. The Y, La, Ce content (% by mass) and the Ti, Zr, Hf content (% by mass) in the separated primary film are quantitatively analyzed by ICP-MS.
[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 12.0 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 12.0 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 12.0 μm, the adhesion of the coating film can be improved while maintaining excellent magnetic properties. The lower limit of Al peak position D Al is preferably 3.0 μm, more preferably 4.0 μm. Al peak position D The preferable upper limit of Al is 11.0 μm, and more preferably 10.0 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 0.03 to 0.2 / 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 0.03 / μm 2, the roots of the primary coating are not sufficiently formed. Therefore, the adhesion of the primary coating to the steel sheet is low. On the other hand, when the Al oxide number density ND exceeds 0.2 pieces / 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 prevent secondary recrystallization and domain wall migration. Harm and reduce magnetic properties. Therefore, the Al oxide number density ND is 0.03 to 0.2 / 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 preferred upper limit of the number density ND is 0.15 pieces / μm 2, and more preferably 0.1 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, an arbitrary 36 μm × 50 μm region (observation region) is subjected to elemental analysis using an energy dispersive X-ray spectroscope (EDS), and the characteristic X of the observation region is performed. Create a map showing the distribution of line 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. 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 ​​specified Al oxide region (area per analysis point in the map showing the distribution of characteristic X-ray intensity × corresponding to the region specified as Al oxide) Analysis score))
Area per analysis point = mapping 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 total content of Y, La and Ce in the primary coating is 0.001 to 4.0% and the total content of Ti, Hf and Zr in the primary coating is 0.0005 to 8.0%. , Al peak position D Al is 2.0 to 12.0 μm, and the number density ND of Al oxides at Al peak position D Al is 0.03 to 0.2 / μm 2.
[0067]
[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 grain-oriented electrical steel sheets includes a cold rolling process, a decarburization annealing process, and a finish annealing process. Hereinafter, each step will be described.
[0068]
[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.
[0069]
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 in 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 hot-rolled steel sheet is 0.005%, the preferable lower limit is 0.02%, and the more preferable lower limit is 0.04%.
[0070]
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 preferable upper limit of the Si content of the hot-rolled steel sheet is 4.0%, and the more preferable upper limit is 3.8%. The preferable lower limit of the Si content of the hot-rolled steel sheet is 2.6%, and the more preferable lower limit is 2.8%.
[0071]
Mn: 0.02-0.2%
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 0.2%, the Mn content of the directional electromagnetic steel sheet after the finish annealing step is 0.02 to 0.2%. The preferred upper limit of the Mn content of the hot-rolled steel sheet is 0.13%, and the more preferable upper limit is 0.1%. The preferable lower limit of the Mn content in the hot-rolled steel sheet is 0.03%, and the more preferable upper limit is 0.04%.
[0072]
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 selected from the group consisting of S and Se is less than 0.005%, the above effect is difficult to obtain. On the other hand, if the total content of one or more 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%.
[0073]
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%.
[0074]
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%, more preferably 0.010%. The preferable lower limit of the N content in the hot-rolled steel sheet is 0.005%, more preferably 0.006%.
[0075]
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.
[0076]
[About arbitrary elements]
The hot-rolled steel sheet according to the present invention may further contain at least one selected from the group consisting of Cu, Sn and Sb in a total of 0.6% or less instead of a part of Fe. All of these elements are arbitrary elements.
[0077]
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 content of one or more selected from the group consisting of Cu, Sn and Sb is 0 to 0.6% in total. The preferred lower limit of the total content of one or more 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 selected from the group consisting of Cu, Sn and Sb is 0.5%, more preferably 0.45%.
[0078]
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.
[0079]
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 elements selected from the group consisting of Bi, Te and Pb is 0.02%, more preferably 0.015%.
[0080] [0080]
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 and 1350 ° C or less. Hot rolling is performed on the heated slab to produce a hot-rolled steel sheet.
[0081]
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).
[0082]
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
[0083]
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.
[0084]
[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 develops in the steel sheet, and the processing strain introduced by the cold rolling process is generated. To be 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.
[0085]
[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.
[0086]
[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.
[0087]
[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 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 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. It is 8.0%, and the total content of the metal compound selected from the group consisting of Ti, Zr, and Hf in terms of oxide is 0.5 to 10.0%, and the Y, La, and so on. The total of the oxide-equivalent total content of the metal compound selected from the group consisting of Ce and the oxide-equivalent total content of the metal compound selected from the group consisting of Ti, Zr, and Hf. Is 2.0 to 14.0%, and 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. It is .15 to 4.0. Hereinafter, the additives in the annealing separator will be described in detail.
[0088]
[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.
[0089]
[Metal compound selected from the group consisting of Y, La, Ce]
Metal compounds (referred to as Y, La, Ce compounds) selected from the group consisting of Y, La and Ce are total in terms of oxides when the MgO content in the annealing separator is 100% by mass. It contains 0.5 to 8.0%. 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.
[0090]
The Y, La, and Ce compounds are compounds in which one or more of the Y, La, and Ce atoms are contained in the compound molecule. Hydroxides, carbonates, sulfates, etc. that change into substances. 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 8.0%, 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 8.0%, the MgO content in the annealing separator is further reduced, so that the formation of Mg 2SiO 4 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 8.0%. The preferable lower limit of the oxide-equivalent content C RE of the Y, La, and Ce compounds is 0.8%, and more preferably 1.2%. The preferable upper limit of the oxide-equivalent content C RE of the Y, La, and Ce compounds is 7.0%, and more preferably 6.5%.
[0091]
[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 are total in terms of oxides when the MgO content in the annealing separator is 100% by mass. It contains 0.5 to 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. ..
[0092]
The Ti, Zr, and Hf compounds are compounds in which one or more of the Ti, Zr, and Hf atoms are contained in the compound molecule. Hydroxides, phosphates, etc. that change into substances. 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 deterioration of the magnetic properties due to the excessive inclusion of the Y, La, and Ce compounds is suppressed, and the roots of the primary coating are contained. It can promote growth and improve the adhesion of the primary coating to the steel sheet. If the oxide-equivalent content C G4 of the Ti, Zr, and Hf compounds is less than 0.5%, 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 Mg 2SiO 4 is suppressed. That is, the reactivity is reduced. When the oxide equivalent content C G4 of the Ti, Zr, and Hf compounds is 0.5 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.
[0093]
The preferable lower limit of the abundance ratio X G4 of Ti, Zr, and Hf atoms is 0.8%, and more preferably 1.5%. The preferred upper limit of the abundance ratio X G4 of Ti, Zr, and Hf atoms is 8.0%, more preferably 7.5%.
[0094]
[X RE / X G4 ratio in annealing separator]
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 (hereinafter referred to as X RE / X G4) is 0.15 to 4 It is in the range of .00. If X RE / X G4 is less than 0.15, root growth of the primary coating is not promoted 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 4.00, the adhesion is deteriorated. As a result, the adhesion of the primary coating to the steel sheet is reduced. When X RE / X G4 is 0.15 to 4.00, the adhesion of the primary coating to the steel sheet is enhanced. The preferred lower limit of X RE / X G4 is 0.25, more preferably 0.50. The preferred upper limit of X RE / X G4 is 3.00, more preferably 2.50.
[0095]
[N RE and NG 4 in annealing separator]
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 contained in the annealing separator. The number density NG4 of particles having a particle size of 0.1 μm or more of the metal compound is 2 billion particles / g or more, respectively. The particle size of these metal compounds is determined as the volume-based equivalent diameter of a sphere, and is a laser. It is obtained from the particle size distribution based on the number of particles obtained by measuring the raw material powder with a 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 release 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 promote oxygen release of Y, La, and Ce, and continuously suppress the aggregation of the internal oxide layer necessary for the development of the coating film. it is conceivable that. Therefore, it is considered that this interaction in oxygen release can be effectively obtained by increasing the number densities N RE and NG 4 to enhance the dispersed state in the separating agent layer. The particle size is a volume-based sphere-equivalent diameter.
[0096]
[Optional component of annealing separator]
The quenching separator further comprises, if necessary, one or more of a metal compound (referred to as Ca, Sr, Ba compound) selected from the group consisting of Ca, Sr and Ba in the annealing separator. The ratio of the total number of Ca, Sr, and Ba atoms to the number of Mg atoms contained in the above may be less than 0.025.
[0097]
When a metal compound selected from the group consisting of Ca, Sr and Ba is contained, the Ca, Sr and Ba compounds are the number of Ca, Sr and Ba atoms with respect to the number of Mg atoms contained in the quenching separator. The content is less than 0.025 as a ratio of the total amount of calcium. Here, one kind of Ca, Sr, Ba compound in the quenching separator is defined as EMA, and the sum of Ca, Sr, Ba atoms of MM with respect to the number of Mg atoms contained in the annealing separator. The ratio x AM can be calculated by the following equation.
x AM = ((Number of Ca atoms per M AM 1 molecule) + (Number of Sr atoms per M AM 1 molecule) + (Number of Ba atoms per M AM 1 molecule)) x (Amount of M AM added (% by mass) / M AM (Molecular weight of) / (100 / Molecular weight of MgO)
Therefore, the ratio of the total number of Ca, Sr, and Ba atoms to the number of Mg atoms contained in the annealing separator to which one or more Ca, Sr, and Ba compounds are added is X AM (hereinafter, Ca, Sr, Ba). The abundance ratio of atoms (referred to as X AM) is the sum of x AM of each of all added Ca, Sr, and Ba compound species.
[0098]
The Ca, Sr, and Ba compounds are, for example, oxides and hydroxides, sulfates, phosphates, borates, and the like that are partially or wholly converted into oxides by the drying treatment and finish annealing treatment described later. 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 Mg 2SiO 4. If at least one of Ca, Sr, and Ba is contained in a small amount, the above effect can be obtained to some extent. On the other hand, when the abundance ratio XAM of Ca, Sr, and Ba atoms is 0.025 or more, the reaction between MgO and SiO 2 is rather delayed, and the formation of Mg 2SiO 4 is suppressed. That is, the reactivity is reduced. When the abundance ratio XAM of Ca, Sr, and Ba atoms is less than 0.025, the formation of Mg 2SiO 4 is promoted in the finish annealing.
[0099]
[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.
[0100]
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.
[0101]
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 12.0 μm from the surface of the primary coating. Further, the Al oxide number density ND is 0.03 to 0.2 / μm 2.
[0102]
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.
[0103]
[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.
[0104]
[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
[0105]
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.
[0106]

[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.
[0107]
[table 1]

[0108]
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.
[0109]
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.
[0110]
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%.
[0111]
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 900 to 1120 ° C. in all test numbers, and the holding time at the annealing temperature was 2 minutes.
[0112]
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) and industrial pure water in a blending ratio of 1: 2. The annealing separator contained MgO and the additives shown in Table 2. The Y, La, Ce content C RE in the annealing separator shown in Table 2 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 abundance ratio X RE of Y, La, and Ce atoms 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 Ti, Zr, Hf content C G4 in the annealing separator shown in Table 2 is the Ti, Zr, Hf oxide equivalent when the MgO content in the annealing separator is 100% by mass. Means total content. Similarly, the abundance ratio X G4 of Ti, Zr, and Hf atoms shown in Table 2 means the ratio of the total number of Ti, Zr, and 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. The particle size is a volume-based sphere-equivalent diameter.
[0113]
[Table 2]

[0114]
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.
[0115]
[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: SALD-3000, Shimadzu Corporation), and the number of particles in 1 g was calculated.
[0116]
[Chemical composition analysis of the base steel sheet of grain-oriented electrical steel sheet]
The base steel sheets of the manufactured directional electromagnetic steel sheets of test numbers 1 to 57 are subjected to alkali washing and light pickling to remove the primary coating and the steel plate of the resurface layer, and then spark discharge emission analysis and atomic absorption spectroscopy. The chemical composition was determined by the analytical method. The obtained chemical composition is shown in Table 3.
[0117]
[Table 3]

[0118]
[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 is plotted in the depth direction from the surface. rice field. 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.
[0119]
[Table 4]

[0120]
[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.
[0121]
[Y, La, Ce content and Ti, Zr, Hf content measurement test 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. Y, La, Ce and Ti, Zr, Hf 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 Y, La, Ce content (mass%) and the Ti, Zr, Hf content (mass%) in the separated primary film were quantitatively analyzed by ICP-MS. Table 4 shows the Y, La, Ce content and the Ti, Zr, Hf content obtained by the measurement.
[0122]
[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. In Table 4, the magnetic flux density of 1.92T or more is indicated by “◯”, 1.88T or more and less than 1.92T is indicated by “Δ”, and the magnetic flux density of less than 1.88T is indicated by “x”. If the magnetic flux density is 1.92T or more (that is, if it is "◯" in Table 4), it is judged that the magnetic characteristics are excellent.
[0123]
[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
[0124]
Table 4 shows the test results. A primary film residual rate of 90% or more is indicated by “◯”, 70% or more and less than 90% is indicated by “Δ”, and less than 70% is indicated by “x”. If the residual ratio of the primary coating is 90% or more (that is, if it is “◯” in Table 4), it is judged that the adhesion of the primary coating to the base steel sheet is excellent.
[0125]
[Test results]
Table 4 shows the test results. With reference to Tables 2 and 4, in test numbers 13, 18, 19, 24, 29, 30, and 42-49, the components of the annealing separator were appropriate. Specifically, in these test numbers, the total content of Y, La, and Ce compounds in terms of oxides when the MgO content in the quenching separator is 100% by mass% C RE (Y, La, Ti, Zr, Hf compounds when the oxide equivalent content C RE) of the Ce compound is in the range of 0.5 to 8.0% and the MgO content in the quenching separator is 100% by mass%. The total oxide-equivalent content C G4 (oxide-equivalent content of Ti, Zr, and Hf compounds C G4) was in the range of 0.5 to 10.0%. Further, the total of the oxide-equivalent content of the Y, La, and Ce compounds and the oxide-equivalent content of the Ti, Zr, and Hf compounds (C RE + C G4) is in the range of 2.0 to 14.0%. It was inside. Further, the ratio of the total number of Y, La, and Ce atoms (X RE / X G4) to the total number of Ti, Zr, and Hf atoms contained in the annealing separator is 0.15 to 4.00. It was within range. Therefore, the Al peak position D Al was in the range of 2.0 to 12.0 μm, and the Al oxide number density ND was 0.03 to 0.2 / μm 2. As a result, in these test numbers, the primary coating showed excellent adhesion. Furthermore, it showed excellent magnetic properties.
[0126]
Further, in particular, test numbers 13, 29, 30, and 45 to 49 contain at least two kinds of metal compounds selected from the group consisting of Ti, Zr, and Hf, and the primary coating has extremely excellent adhesion. And showed extremely excellent magnetic properties.
[0127]
On the other hand, in test numbers 1, 2, 3, 4, 5, and 6, the oxide-equivalent content C RE of the Y, La, and Ce compounds was too low, and the oxide-equivalent content of the Y, La, and Ce compounds was too low. And the total oxide-equivalent content of Ti, Zr, and Hf compounds (C RE + C G4), and the ratio of the total number of Y, La, and Ce atoms to the total number of Ti, Zr, and Hf atoms (X). RE / X G4) was also too low. Therefore, the number density ND of Al peak position D Al and Al oxide was too low. As a result, the adhesion of the primary coating was low.
[0128]
In test numbers 7 and 8, the oxide-equivalent content C RE of the Y, La, and Ce compounds was too low, the oxide-equivalent content of the Y, La, and Ce compounds and the oxide-equivalent of the Ti, Zr, and Hf compounds. The total content of (C RE + C G4) was also 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.
[0129]
In test numbers 9, 20 and 28, none of the Ti, Hf and Zr compounds were contained. Therefore, the Al oxide number density ND was too small. As a result, the adhesion of the primary coating was low.
[0130]
In test numbers 10, 16 and 21, none of the Y, La and Ce compounds were contained. 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.
[0131]
In test numbers 11 and 12, the oxide-equivalent content C RE of the Y, La, and Ce compounds was low. Therefore, the Al peak position D Al was too low. As a result, the adhesion of the primary coating was low.
[0132]
In test numbers 14 and 15, the oxide-equivalent content C G4 of the Ti, Zr, and Hf compounds was low, and the ratio of the total number of Y, La, and Ce atoms to the total number of Ti, Zr, and Hf atoms (X RE). / X G4) was high. Therefore, the Al oxide number density ND was too low. As a result, the adhesion of the primary coating was low.
[0133]
In test number 17, the oxide-equivalent content C RE of the Y, La, and Ce compounds was too low, and the ratio of the total number of Y, La, and Ce atoms to the total number of Ti, Zr, and Hf atoms (X RE). / X G4) 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.
[0134]
In test numbers 22 and 23, the oxide-equivalent content C G4 of the Ti, Zr, and Hf compounds is too high, and the ratio of the total number of Y, La, and Ce atoms to the total number of Ti, Zr, and Hf atoms. (X RE / X G4) was too low. Therefore, the Al peak position D Al was too low. As a result, the adhesion of the primary coating was low.
[0135]
In test numbers 25, 26, and 27, the ratio of the total number of Y, La, and Ce atoms to the total number of Ti, Zr, and Hf atoms (X RE / X G4) was too high. Therefore, the Al oxide number density ND was too small. As a result, the adhesion of the primary coating was low.
[0136]
In Test No. 31, the total of the oxide-equivalent contents of the Y, La, and Ce compounds CRE, the oxide-equivalent content of the Y, La, and Ce compounds, and the oxide-equivalent content of the Ti, Zr, and Hf compounds. (C RE + C G4) was too high. Therefore, the Al peak position D Al was too high, and the Al oxide number density ND was too high. As a result, the magnetic properties were low.
[0137]
In test number 32, the oxide-equivalent content C RE of the Y, La, and Ce compounds was too high. Therefore, the Al peak position D Al was too high. As a result, the magnetic properties were low.
[0138]
In test number 33, the oxide-equivalent content C G4 of the Ti, Zr, and Hf compounds was too high. Therefore, the Al oxide number density ND was too high. As a result, the magnetic properties were low.
[0139]
In test number 34, the oxide-equivalent content C G4 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.
[0140]
In test numbers 35, 36, 37, 38, and 39, the ratio of the total number of Y, La, and Ce atoms to the total number of Ti, Zr, and Hf atoms (X RE / X G4) was too low. Therefore, the Al peak position D Al was too low. As a result, the adhesion of the primary coating was low.
[0141]
In test number 40, the total of the oxide-equivalent content of the Y, La, and Ce compounds and the oxide-equivalent content of the Ti, Zr, and Hf compounds (C RE + C G4) 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.
[0142]
In test number 41, the total of the oxide-equivalent content of the Y, La, and Ce compounds and the oxide-equivalent content of the Ti, Zr, and Hf compounds (C RE + C G4) was too high. Therefore, the Al peak position D Al was too high, and the Al oxide number density ND was too high. As a result, the magnetic properties were low.
[0143]
In test numbers 50 to 53, 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.
[0144]
In test numbers 54 to 57, 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.
[0145]

[Manufacturing of grain-oriented electrical steel sheets]
In the same manner as in Example 1, an aqueous slurry was applied to the cold-rolled steel sheet after primary recrystallization annealing manufactured from molten steel having the chemical components shown in Table 1 and dried to obtain an annealed separator. 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: 2. The quenching separators are MgO, the additives shown in Table 5, 2.5% CeO 2 and 4.0% ZrO 2, 2.0% when the MgO content is 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 abundance ratio X RE of Y, La, and Ce atoms 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 abundance ratio X G4 of Ti, Zr, and Hf atoms shown in Table 5 means the ratio of the total number of Ti, Zr, and Hf atoms to the number of Mg atoms contained in the quenching separator. Similarly, the abundance ratio XAM of Ca, Sr, and Ba atoms shown in Table 5 means the ratio of the total number of Ca, Sr, and Ba atoms to the number of Mg atoms contained in the quenching separator.
[0146]
[Table 5]

[0147]
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.
[0148]
[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 58 to 70 was determined by the spark discharge emission analysis method and the atomic absorption spectroscopy. The obtained chemical composition is shown in Table 6.
[0149]
[Table 6]

[0150]
[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 and the Ti, Zr, Hf content were determined. Table 7 shows the Al peak position D Al obtained by measurement, the Al oxide number density ND, the Y, La, Ce content and the Ti, Zr, Hf content in the primary coating.
[0151]
[Table 7]

[0152]
[Magnetic characterization test]
The magnetic properties of the grain-oriented electrical steel sheets of each test number were evaluated by the same method as in Example 1. Table 7 shows the test results. Similar to Example 1, in Table 7, the magnetic flux density of 1.92T or more is indicated by “◯”, 1.88T or more and less than 1.92T is indicated by “Δ”, and the magnetic flux density of less than 1.88T is indicated by “x”. If the magnetic flux density is 1.92T or more (that is, if it is "◯" in Table 7), it is judged that the magnetic characteristics are excellent.
[0153]
[Adhesion evaluation test]
The adhesion of the primary film of the grain-oriented electrical steel sheet of each test number was evaluated by the same method as in Example 1. Table 7 shows the test results. Similar to Example 1, in Table 7, the primary film residual ratio of 90% or more is indicated by “◯”, 70% or more and less than 90% is indicated by “Δ”, and less than 70% is indicated by “x”. If the residual ratio of the primary coating is 90% or more (that is, if it is "◯" in Table 7), it is judged that the adhesion of the primary coating to the base steel sheet is excellent.
[0154]
[Test results]
Table 7 shows the test results. With reference to Tables 5 and 7, in test numbers 58-60, 62-64, 66-70, the components of the annealing separator were appropriate. Specifically, the total content in terms of oxides of Y, La, and Ce compounds when the MgO content in the annealing separator is 100% by mass% C RE (Oxide conversion of Y, La, Ce compounds). The total oxide conversion of Ti, Zr, and Hf compounds when the content C RE) is in the range of 0.5 to 8.0% and the MgO content in the quenching separator is 100% by mass%. The content C G4 (oxide-equivalent content C G4 of Ti, Zr, Hf compounds) was in the range of 0.5 to 10.0%. Further, the total of the oxide-equivalent content of the Y, La, and Ce compounds and the oxide-equivalent content of the Ti, Zr, and Hf compounds (C RE + C G4) is in the range of 2.0 to 14.0%. It was inside. Further, the ratio of the total number of Y, La, and Ce atoms (X RE / X G4) to the total number of Ti, Zr, and Hf atoms contained in the annealing separator is 0.15 to 4.00. It was within range. Furthermore, the ratio (XAM) of the total number of Ca, Sr, and Ba atoms to the number of Mg atoms contained in the quenching separator was less than 0.025. Therefore, the Al peak position D Al was in the range of 2.0 to 12.0 μm, and the Al oxide number density ND was 0.03 to 0.2 / μm 2. As a result, in these test numbers, the primary coating showed excellent adhesion. Furthermore, it showed excellent magnetic properties.
[0155]
On the other hand, in test numbers 61 and 65, the ratio (XAM) of the total number of Ca, Sr, and Ba atoms to the number of Mg atoms contained in the annealing separator was 0.025 or more. Therefore, the Al peak position D Al was too low. As a result, the adhesion of the primary coating was low.
[0156]
The embodiment of the present invention has been described above. However, the embodiments described above are merely examples for carrying out the present invention. Therefore, the present invention is not limited to the above-described embodiment, and the above-mentioned embodiment can be appropriately modified and carried out within a range not deviating from the gist thereof.
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 12.0 μm,
It is an Al oxide at the peak position of the Al emission intensity, and the number density of the Al oxide having a diameter equivalent to a circle based on an area of ​​0.2 μm or more is 0.03 to 0.2 / μm 2. , Directional electromagnetic steel plate.
[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 8. 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 0.5 to 10.0%.
Further, the total content of the metal compound selected from the group consisting of Y, La and Ce in terms of oxide and the oxide conversion of the compound of the metal selected from the group consisting of Ti, Zr and Hf are converted into oxides. The total with the total content of is 2.0 to 14.0%,
Furthermore, 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 4.00.
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. be,
Manufacturing method of grain-oriented electrical steel sheet.
[Claim 3]
The method for manufacturing grain-oriented electrical steel sheets according to claim 2.
The annealing separator is further
Contains at least one metal compound selected from the group consisting of Ca, Sr, and Ba,
The ratio of the total number of Ca, Sr, and Ba atoms to the number of Mg atoms contained in the quenching separator is less than 0.025.
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 at least one selected from the group consisting of Cu, Sb and Sn in a total of 0.6% or less.
[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 selected from the group consisting of Bi, Te and Pb.
[Claim 6]
Annealing separator used in the manufacture of grain-oriented electrical steel sheets
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 8. 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 0.5 to 10.0%.
Further, the total content of the metal compound selected from the group consisting of Y, La and Ce in terms of oxide and the oxide conversion of the compound of the metal selected from the group consisting of Ti, Zr and Hf are converted into oxides. The total with the total content of is 2.0 to 14.0%,
Furthermore, the ratio of the total number of Y, La, and Ce atoms to the total number of Ti, Zr, and Hf atoms contained in the annealing separator is 0.15 to 4.00.
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. be,
Annealing separator.
[Claim 7]
The annealing separator according to claim 6,
The annealing separator further contains at least one metal compound selected from the group consisting of Ca, Sr, and Ba.
Further, the annealing separator in which the ratio of the total number of Ca, Sr, and Ba atoms to the number of Mg atoms contained in the annealing separator is less than 0.025.