Title of invention: Directional electromagnetic steel plate
Technical field
[0001]
The present invention relates to a directional electromagnetic steel plate.
This application claims priority based on Japanese Patent Application No. 2019-170881 filed in Japan on September 19, 2019, and the contents thereof are incorporated herein by reference.
Background technology
[0002]
The directional electromagnetic steel plate is a steel plate containing 0.5 to 7% of Si in mass% and having the crystal orientation integrated in the {110} <001> orientation (goth orientation). Directional electromagnetic steel sheets are used as soft magnetic materials for iron core materials of transformers and other electrical equipment.
[0003]
Normally, the directional electromagnetic steel plate includes a base steel plate, a glass coating, and a tensioning insulating coating. The glass coating is formed on the base steel plate. The tensioning insulating coating is formed on the glass coating. By providing a tensioning insulating film and a glass film, the insulating property between the steel plates is enhanced and the magnetic efficiency is enhanced.
[0004]
The glass film is an oxide mainly composed of forsterite (Mg 2SiO 4), which contributes to tension application and insulation. The glass coating also has a role of enhancing the adhesion of the tension-applied insulating coating to the base steel plate. Therefore, it is required to improve the adhesion of the glass coating to the base steel plate.
[0005]
Techniques for improving the adhesion of the glass coating to the base steel plate are described in Japanese Patent Application Laid-Open No. 2012-214902 (Patent Document 1), Japanese Patent Application Laid-Open No. 2018-53346 (Patent Document 2), and Japanese Patent Application Laid-Open No. 11 -No. 61356 (Patent Document 3).
[0006]
The directional electromagnetic steel plate disclosed in Patent Document 1 is a directional electromagnetic steel plate containing Si: 1.8 to 7% in mass% and having a primary coating containing forsterite as a main component on the surface thereof. It is characterized by containing one or more of Ce, La, Pr, Nd, Sc, and Y in an amount of 0.001 to 1000 mg / m 2 per side.
[0007]
The directional electromagnetic steel plate disclosed in Patent Document 2 is characterized in that the void area ratio in the cross section of the glass coating formed between the insulating coating and the mother steel plate is 20% or less.
[0008]
In the directional electromagnetic steel plate disclosed in Patent Document 3, the peak intensity of Si obtained by glow discharge emission analysis performed from the surface of the oxide film is 1/2 or more of the peak intensity of Al, and the peak of Si is from the surface of the oxide film. The depth to the position is within 1/10 of the depth from the surface of the oxide film to the peak position of Al.
Prior art literature
Patent documents
[0009]
Patent Document 1: Japanese Patent Application Laid-Open No. 2012-214902
Patent Document 2: Japanese Patent Application Laid-Open No. 2018-53346
Patent Document 3: Japanese Patent Application Laid-Open No. 11-613356
Outline of the invention
Problems to be solved by the invention
[0010]
Even in the above-mentioned Patent Documents 1 to 3, the adhesion of the glass film is enhanced. However, other configurations may enhance the adhesion of the glass coating.
[0011]
The present invention has been made in view of the above problems, and an object of the present invention is to provide a directional electromagnetic steel plate having excellent adhesion of a glass coating.
Means to solve the problem
[0012]
The gist of the present invention is as follows.
(1) The directional electromagnetic steel plate according to one aspect of the present invention is
Base steel plate and
The glass coating placed on the base steel plate and
With a tension-applying insulating film arranged on the glass film,
The average chemical composition of the base steel plate and the glass coating is% by mass.
C: 0.010% or less,
Si: 2.5-4.0%,
Mn: 0.01-1.00%,
N: 0.010% or less,
Sol. Al: 0.010% or less,
Insol. Al: 0.005 to 0.030%,
Mg: 0.05 to 0.20%,
O: 0.05 to 0.40%,
Ti: 0 to 0.020%,
S: 0.010% or less,
P: 0.030% or less,
Sn: 0 to 0.50%,
Cr: 0 to 0.50%,
Cu: 0 to 0.50%,
Bi: 0-0.0100%,
Se: 0-0.020%,
Sb: 0 to 0.50% and
The rest consists of Fe and impurities
Regarding the glow emission spectral spectra of Al and Si obtained by performing glow discharge emission analysis in the depth direction from the surface of the glass coating.
The surface of the glass coating was set as the measurement start time Ts.
The time when Al becomes the maximum emission intensity is defined as T Al p,
The emission intensity of Al at the T Al p is defined as F (T Al p).
The time when Si becomes the maximum emission intensity is defined as TSip,
When the emission intensity of Al in the T Ship is defined as F (T Ship),
The Ts, the T Al p, the F (T Al p), the T S p, and the F (T S p)
0.05 ≤ F (TS i p) / F (T Al p) ≤ 0.50, and
2.0 ≤ (T Al p-Ts) / (TS i p-Ts) ≤ 5.0
Meet.
(2) In the directional electromagnetic steel plate according to (1) above, the plate thickness of the base steel plate may be 0.17 mm or more and less than 0.22 mm.
(3) With the directional electromagnetic steel plate described in (1) or (2) above,
As the average chemical composition, in mass%,
Cr: 0.01-0.50%,
Sn: 0.01-0.50%,
Cu: 0.01-0.50%,
Bi: 0.0010-0.0100%,
Se: 0.001 to 0.020%, and
Sb: 0.01-0.50%,
It may contain at least one element selected from the group consisting of.
(4) In the directional electromagnetic steel plate according to any one of (1) to (3) above,
Regarding the glow emission spectral spectra of Al and Fe obtained by performing glow discharge emission analysis in the depth direction from the surface of the glass coating.
The time when Al becomes the maximum emission intensity is defined as T Al p,
The time when the Fe emission intensity becomes 60% of the saturation value of the Fe emission intensity is defined as T Fe 60.
When the time when the Fe emission intensity becomes 90% of the saturation value of the Fe emission intensity is defined as T Fe 90,
The T Al p, the T Fe 60, and the T Fe 90 are
T Fe 60 ≤ T Al p ≤ T Fe 90
May be satisfied.
Effect of the invention
[0013]
According to the above aspect of the present invention, it is possible to provide a directional electromagnetic steel plate having excellent adhesion of the glass coating.
A brief description of the drawing
[0014]
FIG. 1 is a perspective view showing a directional electromagnetic steel plate according to an embodiment of the present invention.
FIG. 2 is a perspective view showing a modified example of the directional electromagnetic steel plate according to the present embodiment.
FIG. 3 is a diagram showing glow emission spectral spectra of Al and Si obtained by glow discharge emission analysis.
FIG. 4 is a perspective view showing a state in which the tension-applied insulating film is removed from the directional electromagnetic steel plate according to the present embodiment.
FIG. 5 is a flow chart showing an example of a manufacturing process of a directional electromagnetic steel plate according to the present embodiment.
Embodiment for carrying out the invention
[0015]
Hereinafter, preferred embodiments of the present invention will be described in detail. However, the present invention is not limited to the configuration disclosed in the present embodiment, and various modifications can be made without departing from the gist of the present invention. In addition, the lower limit value and the upper limit value are included in the numerical limitation range described below. Numerical values ​​that indicate "greater than or equal to" or "less than" do not fall within the numerical range. “%” Regarding the content of each element means “% by mass” unless otherwise specified.
[0016]
First, the present inventors first set the chemical composition of the base steel plate (the average chemical composition of the base steel plate and the glass coating) in terms of mass%, C: 0.010% or less, Si: 2.5 to 4.0%, and so on. Mn: 0.01 to 1.00%, N: 0.010% or less, sol. Al: 0.010% or less, insol. Al: 0.005 to 0.030%, Mg: 0.05 to 0.20%, O: 0.05 to 0.40%, Ti: 0 to 0.020%, S: 0.010% or less, P: 0.030% or less, Sn: 0 to 0.50%, Cr: 0 to 0.50%, Cu: 0 to 0.50%, Bi: 0 to 0.0100%, Se: 0 to 0. 020%, Sb: 0 to 0.50%, and a directional electromagnetic steel plate whose balance was Fe and impurities were targeted. This directional electromagnetic steel plate was studied for the purpose of improving the adhesion of the glass coating.
[0017]
As mentioned above, the adhesion of the glass coating on the directional electromagnetic steel plate is also an issue in the previous research. In order to improve the adhesion of the glass coating, in the conventional research, for example, the following approach is taken.
(A) By adjusting the quenching separator, the adhesion of the glass film is enhanced.
(B) By controlling the form of SiO 2 formed on the surface layer of the base steel plate before finish baking, the adhesion of the glass film is enhanced. Specifically, the morphology of SiO 2 is controlled by devising a decarburization and annealing step to improve the adhesion of the glass film.
[0018]
However, the present inventors have studied to improve the adhesion of the glass coating by a completely different approach from the conventional one. As a result of the examination, it was found that if the spinel (MgAl 2O 4) is localized in the vicinity of the interface with the base steel plate in the glass coating, the adhesion of the glass coating is enhanced. The present inventors have found for the first time the finding that the adhesion of the glass film is enhanced by the localization of the spinel near the interface.
[0019]
The localization of spinel to the interface in the glass film can be specified by the following method using glow discharge emission analysis. Specifically, after removing the tension-applied insulating film, glow discharge emission analysis is performed in the depth direction from the surface of the glass film to show the emission intensity of Al and the emission intensity of Si (Al). GDS spectrum, GDS spectrum of Si) is obtained. The surface of the glass coating is defined as the measurement start time Ts, the time when Al becomes the maximum emission intensity in the GDS spectrum of Al is defined as T Al p, and the emission intensity of Al at the time T Al p is F (T Al p). In the GDS spectrum of Si, the time when Si has the maximum emission intensity is defined as TSip, and the emission intensity of Al at the time TSip is defined as F (TSip) (that is, Si). The emission intensity of Al at the peak position of the emission intensity of is defined as F (TSip)). At this time, if the following equations (1) and (2) are satisfied, it can be determined that the spinel is sufficiently localized in the vicinity of the interface with the base steel plate in the glass coating.
0.05 ≤ F (TS i p) / F (T Al p) ≤ 0.50 ... (Equation 1)
2.0 ≤ (T Al p-Ts) / (TS i p-Ts) ≤ 5.0 ... (Equation 2)
[0020]
Regarding the directional electromagnetic steel plate, the reason why the adhesion of the glass coating is improved when the spinel is localized near the interface, that is, when the formulas (1) and (2) are satisfied, is not clear at this time. However, the following reasons can be considered. Fine irregularities are formed on the surface of the base steel plate. When the spinel is present in the vicinity of the interface with the base steel plate in the glass coating, the spinel is fitted into the recess on the surface of the base steel plate. Therefore, it is considered that the spinel exerts an anchor effect and enhances the adhesion of the glass coating to the base steel plate. It is possible that a mechanism different from this mechanism enhances the adhesion of the glass coating to the base steel plate. However, it is also demonstrated in the examples below that the adhesion of the glass coating to the base steel plate is enhanced if the formulas (1) and (2) are satisfied.
[0021]
The directional electromagnetic steel plate according to the present embodiment completed based on the above findings has the following configuration.
[0022]
The directional electromagnetic steel plate according to this embodiment is
Base steel plate and
The glass coating placed on the base steel plate and
With a tension-applying insulating film placed on the glass film,
The average chemical composition of the base steel plate and glass coating is% by mass.
C: 0.010% or less,
Si: 2.5-4.0%,
Mn: 0.01-1.00%,
N: 0.010% or less,
Sol. Al: 0.010% or less,
Insol. Al: 0.005 to 0.030%,
Mg: 0.05 to 0.20%,
O: 0.05 to 0.40%,
Ti: 0-0.0 20%,
S: 0.010% or less,
P: 0.030% or less,
Sn: 0 to 0.50%,
Cr: 0 to 0.50%,
Cu: 0 to 0.50%,
Bi: 0-0.0100%,
Se: 0-0.020%,
Sb: 0 to 0.50% and
The rest consists of Fe and impurities
Regarding the glow emission spectral spectra of Al and Si obtained by performing glow discharge emission analysis in the depth direction from the surface of the glass coating.
The surface of the glass coating was set as the measurement start time Ts.
The time when Al becomes the maximum emission intensity is defined as T Al p,
The emission intensity of Al at T Al p is defined as F (T Al p).
The time when Si becomes the maximum emission intensity is defined as TSip,
When the emission intensity of Al in TSip is defined as F (TSip),
The Ts, the T Al p, the F (T Al p), the T S p, and the F (T S p)
0.05 ≤ F (TS i p) / F (T Al p) ≤ 0.50, and
2.0 ≤ (T Al p-Ts) / (TS i p-Ts) ≤ 5.0
Meet.
[0023]
In the above-mentioned directional electromagnetic steel plate, the spinel is sufficiently localized in the vicinity of the interface between the glass coating and the base steel plate in the glass coating. Therefore, the adhesion of the glass film is improved.
[0024]
Further, in the above-mentioned directional electromagnetic steel plate, the plate thickness of the base steel plate may be 0.17 mm or more and less than 0.22 mm.
[0025]
In addition, in the above-mentioned directional electromagnetic steel plate, as the above-mentioned average chemical composition, in mass%,
Cr: 0.01-0.50%,
Sn: 0.01-0.50%,
Cu: 0.01-0.50%,
Bi: 0.0010-0.0100%,
Se: 0.001 to 0.020%, and
Sb: 0.01-0.50%,
It may contain at least one element selected from the group consisting of.
[0026]
Also, with the above directional electromagnetic steel plate,
Regarding the glow emission spectral spectra of Al and Fe obtained by performing glow discharge emission analysis in the depth direction from the surface of the glass coating.
The time when Al becomes the maximum emission intensity is defined as T Al p,
The time when the Fe emission intensity becomes 60% of the saturation value of the Fe emission intensity is defined as T Fe 60.
When the time when the Fe emission intensity becomes 90% of the saturation value of the Fe emission intensity is defined as T Fe 90,
The T Al p, the T Fe 60, and the T Fe 90 are
T Fe 60 ≤ T Al p ≤ T Fe 90
May be satisfied.
[0027]
Hereinafter, the details of the directional electromagnetic steel plate according to this embodiment will be described.
[0028]
[About the composition of the directional electromagnetic steel plate]
FIG. 1 is a perspective view showing a directional electromagnetic steel plate according to the present embodiment. As shown in FIG. 1, the directional electromagnetic steel plate 1 according to the present embodiment includes a base steel plate 10, a glass coating 11, and a tensioning insulating coating 12. The glass coating 11 is arranged on the base steel plate 10. In FIG. 1, the glass coating 11 is arranged on the surface of the base steel plate 10 in direct contact with the surface of the base steel plate 10. The tensioning insulating film 12 is arranged on the glass film 11. In FIG. 1, the tensioning insulating film 12 is arranged on the surface of the glass film 11 in direct contact with the surface of the glass film 11.
[0029]
In FIG. 1, the glass coating 11 and the tensioning insulating coating 12 are formed only on one surface of the base steel plate 10. However, as shown in FIG. 2, the glass coating 11 and the tensioning insulating coating 12 may be formed on a pair of surfaces of the base steel plate 10.
[0030]
[About the average chemical composition of the base steel plate 10 and the glass coating 11]
The chemical composition of the base steel plate 10 provided with the glass coating 11 (the average chemical composition of the base steel plate 10 and the glass coating 11) after the tensioning insulating coating 12 is removed can be obtained by a well-known component analysis method. .. The component analysis method is, for example, as follows.
[0031]
First, the tensioning insulating film 12 is removed from the directional electromagnetic steel plate 1. Specifically, the directional electromagnetic steel plate 1 is immersed in an aqueous sodium hydroxide solution at 80 to 90 ° C. for 7 to 10 minutes, containing NaOH: 30 to 50% by mass and H 2O: 50 to 70% by mass. The soaked steel plate (base steel plate 10 provided with the glass coating 11 from which the tensioning insulating coating 12 has been removed) is washed with water. After washing with water, dry it with a warm air blower for a little less than 1 minute. By the above treatment, the tensioning insulating film 12 is removed, and the base steel plate 10 provided with the glass film 11 is obtained.
[0032]
A well-known component analysis method is carried out on the base steel plate 10 provided with the glass coating 11 after the tensioning insulating coating 12 is removed. Specifically, a drill is used to generate chips from the base steel plate 10 provided with the glass coating 11, and the chips are collected. The collected chips are dissolved in acid to obtain a solution. ICP-AES (Industrial Group Plusma Atomic Emission Spectrometri) is carried out on the solution to carry out elemental analysis of the chemical composition.
[0033]
Si in the chemical composition of the base steel plate 10 provided with the glass coating 11 is determined by the method specified in JIS G1212 (1997) (the method for quantifying silica). Specifically, when the above-mentioned chips are dissolved in an acid, silicon oxide precipitates as a precipitate. This precipitate (silicon oxide) is filtered out with a filter paper, and the mass is measured to determine the Si content.
[0034]
The C content and S content are determined by a well-known high-frequency combustion method (combustion-infrared absorption method). Specifically, the above-mentioned solution is burned in an oxygen stream by high-frequency induction heating to detect the generated carbon dioxide and sulfur dioxide, and the C content and the S content are obtained.
[0035]
The N content is determined using the well-known inert gas melting-heat conductivity method. The O content is determined using a well-known inert gas melting-non-dispersive infrared absorption method.
[0036]
By the above analysis method, the chemical composition of the base steel plate 10 provided with the glass coating 11 (the average chemical composition of the base steel plate 10 and the glass coating 11) can be obtained.
[0037]
The directional electromagnetic steel plate according to the present embodiment contains a basic element as the above average chemical composition, a selective element as necessary, and the balance is composed of Fe and impurities. Hereinafter, "%" for an element means mass% unless otherwise specified.
[0038]
C: 0.010% or less
Carbon (C) is a selective element. C is an essential element for slabs in order to improve the magnetic flux density. However, C is removed from the steel plate in the manufacturing process of the directional electromagnetic steel plate. If C remains in excess of 0.010% as the above average chemical composition, C forms cementite (Fe 3C) even if the content of other elements is within the range of this embodiment, and is directional. Deteriorates iron loss of electromagnetic steel plate. Therefore, the C content is 0.010% or less. The preferred upper limit of the C content is 0.006%, more preferably 0.003%. The C content is preferably as low as possible. Therefore, the C content may be 0%. However, excessive reduction of C content raises manufacturing costs. Therefore, the preferred lower limit of the C content is more than 0%, more preferably 0.001%.
[0039]
Si: 2.5-4.0%
Silicon (Si) is a basic element. Si increases the electrical resistance (specific resistance) of the steel material and reduces the iron loss of the directional electromagnetic steel plate. If the Si content is less than 2.5%, even if the content of other elements is within the range of this embodiment, the steel undergoes phase transformation in the finish baking step, and secondary recrystallization sufficiently proceeds. do not do. As a result, the above effect cannot be sufficiently obtained. On the other hand, if the Si content exceeds 4.0%, the steel plate becomes brittle even if the content of other elements is within the range of the present embodiment, and the plate-passability in the manufacturing process is significantly reduced. Therefore, the Si content is 2.5 to 4.0%. The lower limit of the Si content is preferably 2.8%, more preferably 3.0%, still more preferably 3.2%. The preferred upper limit of the Si content is 3.7%, more preferably 3.6%, still more preferably 3.5%.
[0040]
Mn: 0.01-1.00%
Manganese (Mn) is a basic element. Mn increases the specific resistance of the directional electromagnetic steel plate and reduces iron loss. Mn further enhances hot workability and suppresses the occurrence of cracks in hot rolling. Mn further combines with S and / or Se to form fine MnS and / or fine MnSe. Fine MnS and fine MnSe serve as precipitation nuclei of fine AlN utilized as inhibitors. Therefore, if the amount of fine MnS and fine MnSe deposited is large, a sufficient amount of fine AlN can be obtained. If the Mn content is less than 0.01%, a sufficient amount of fine MnS and fine MnSe will not be deposited even if the content of other elements is within the range of the present embodiment. On the other hand, if the Mn content exceeds 1.00%, the magnetic flux density of the directional electromagnetic steel plate decreases and the iron loss also deteriorates even if the content of other elements is within the range of the present embodiment. Therefore, the Mn content is 0.01 to 1.00%. The preferred lower limit of the Mn content is 0.02%, more preferably 0.03%, still more preferably 0.05%. The preferred upper limit of the Mn content is 0.70%, more preferably 0.50%, still more preferably 0.30%, still more preferably 0.10%.
[0041]
N: 0.010% or less
Nitrogen (N) is a selective element. N combines with Al to form AlN during the manufacturing process of the directional electromagnetic steel plate, and functions as an inhibitor. Therefore, N is an essential element for the slab, which is the material of the directional electromagnetic steel plate. However, N escapes from the steel plate in the manufacturing process of the directional electromagnetic steel plate. If the N content exceeds 0.010% as the above average chemical composition, a large number of blister (pores) are likely to be generated in the steel plate even if the content of other elements is within the range of the present embodiment. Blister causes film defects and reduces the insulation of the directional electromagnetic steel plate. Therefore, the N content is 0.010% or less. The preferred upper limit of the N content is 0.008%, more preferably 0.006%, still more preferably 0.004%. The N content may be 0%. However, it may be difficult to excessively reduce the N content. Therefore, the preferred lower limit of the N content is 0.001%, more preferably 0.002%.
[0042]
Sol. Al: 0.010% or less
Acid-soluble aluminum (sol.Al) is a selective element. sol. Al combines with N to form AlN during the manufacturing process of the directional electromagnetic steel plate, and functions as an inhibitor. However, sol. If the Al content exceeds 0.010%, Al-based inclusions remain in the steel plate even if the content of other elements is within the range of the present embodiment. In this case, the iron loss of the directional electromagnetic steel plate deteriorates. Therefore, sol. The Al content is 0.010% or less. sol. The preferred upper limit of the Al content is 0.008%, more preferably 0.006%. sol. The Al content may be 0%. However, it may be difficult to excessively reduce the Al content. Therefore, the preferred lower limit of the Al content is 0.001%, more preferably 0.002%. In this embodiment, sol. Al means acid-soluble Al. Therefore, sol. The Al content is the content of acid-soluble Al.
[0043]
Insol. Al: 0.005 to 0.030%
Acid-insoluble aluminum (insol.Al) is a basic element. insol. Al is mainly derived from spinel (MgAl 2O 4) formed in the finish annealing step described later. insol. If the Al content is less than 0.005%, even if the content of other elements is within the range of the present embodiment, the glass film 11 does not have sufficient spinel, so that the adhesion of the glass film 11 is low. .. On the other hand, insol. If the Al content exceeds 0.030%, the content of other elements is within the range of this embodiment.However, the spinel is excessively generated. In this case, the spinel is excessively present not only at the interface between the glass coating 11 and the base steel plate 10 but also inside the glass coating 11. If the spinel is excessively present inside the glass coating 11, it becomes a source of cracks in the glass coating 11, and the adhesion of the glass coating 11 is lowered. Therefore, insol. The Al content is 0.005 to 0.030%. insol. The lower limit of the Al content is preferably 0.006%, more preferably 0.007%, still more preferably 0.010%. insol. The preferred upper limit of the Al content is 0.027%, more preferably 0.025%, still more preferably 0.020%.
[0044]
In addition, sol. Al and insol. The Al content may be determined by the following method. sol. For Al, follow the method for quantifying acid-soluble aluminum described in JIS G1257-10-2: 2013 (Aluminum quantification method-acid-soluble aluminum quantification method). Further, from the total aluminum content obtained according to the total aluminum quantification method described in JIS G1257-10-1: 2013 (aluminum quantification method-acid decomposition frame method), the above sol. The value obtained by subtracting the Al content is insol. Defined as Al content.
[0045]
Mg: 0.05 to 0.20%
Magnesium (Mg) is a constituent element (basic element) of the glass film. Therefore, the Mg content may be 0.05 to 0.20%. The preferred upper limit of the Mg content is 0.18%, more preferably 0.16%. The preferred lower limit of the Mg content is 0.08%, more preferably 0.10%.
[0046]
O: 0.05 to 0.40%
Oxygen (O) is a constituent element (basic element) of the glass film. Therefore, the O content may be 0.05 to 0.40%. The preferred upper limit of the O content is 0.30%, more preferably 0.25%. The lower limit of the O content is preferably 0.10%, more preferably 0.15%.
[0047]
Ti: 0 to 0.020%
Titanium (Ti) is a selective element. Ti promotes the formation of a glass film and preferably ensures film adhesion. Therefore, the Ti content may be 0 to 0.020%. The preferred upper limit of the Ti content is 0.015%, more preferably 0.010%. The Ti content may be 0%, but the preferred lower limit of the Ti content is 0.001%, more preferably 0.003%, still more preferably 0.005%.
[0048]
S: 0.010% or less
Sulfur (S) is a selective element. S binds to Mn during the manufacturing process to form the inhibitor fine MnS. Therefore, S is an essential element for slabs. However, S escapes from the steel plate in the manufacturing process of the directional electromagnetic steel plate. If the S content exceeds 0.010% as the above average chemical composition, MnS remains in the base steel plate 10 even if the content of other elements is within the range of the present embodiment, so that iron loss occurs. to degrade. Therefore, the S content is 0.010% or less. The preferred upper limit of the S content is 0.008%, more preferably 0.006%, still more preferably 0.004%. The S content may be 0%. However, it may be difficult to excessively reduce the S content. Therefore, the preferred lower limit of the S content is 0.001%, more preferably 0.002%.
[0049]
P: 0.030% or less
Phosphorus (P) is a selective element. P lowers the workability of the steel plate at the time of rolling. If the P content exceeds 0.030%, the workability of the steel plate is significantly reduced even if the content of other elements is within the range of the present embodiment. Therefore, the P content is 0.030% or less. The preferred upper limit of the P content is 0.020%, more preferably 0.010%. The P content may be 0%. However, it may be difficult to excessively reduce the P content. Therefore, the preferred lower limit of the P content is 0.001%. In addition, P improves the texture and improves the magnetic properties of the steel plate. The preferable lower limit of the P content for effectively exerting this effect is 0.002%, and more preferably 0.005%.
[0050]
The directional electromagnetic steel plate according to this embodiment contains impurities as the above average chemical composition. Here, the impurities are elements mixed from ore or scrap as a raw material, elements mixed from the manufacturing environment, etc., or completely purified by purification and annealing when industrially manufacturing a directional electromagnetic steel plate. It means an element or the like that remains in the steel without being allowed and is allowed within a range that does not adversely affect the directional electromagnetic steel plate according to the present embodiment.
[0051]
The directional electromagnetic steel plate according to the present embodiment has at least one selected from the group consisting of Cr, Sn, Cu, Bi, Se, and Sb in place of a part of Fe, which is the balance, as the above average chemical composition. It may contain an element.
[0052]
Cr: 0 to 0.50%
Chromium (Cr) is a selective element. That is, the Cr content may be 0%. When Cr is contained, Cr enhances the adhesion of the glass coating 11 to the base steel plate 10 in the same manner as Sn and Cu. Cr further enhances the degree of integration of Goth-oriented crystal grains by secondary recrystallization. If even a small amount of Cr is contained, the above effect can be obtained to some extent. However, if the Cr content exceeds 0.50%, Cr oxide is generated even if the content of other elements is within the range of the present embodiment, and the magnetic properties of the directional electromagnetic steel plate 1 are deteriorated. .. Therefore, the Cr content is 0 to 0.50%. The preferred upper limit of the Cr content is 0.40%, more preferably 0.30%, still more preferably 0.20%, still more preferably 0.10%. The lower limit of the Cr content is preferably more than 0%, more preferably 0.01%, still more preferably 0.03%, still more preferably 0.05%.
[0053]
Sn: 0 to 0.50%
Tin (Sn) is a selective element. That is, the Sn content may be 0%. When Sn is contained, Sn enhances the adhesion of the glass coating 11 to the base steel plate 10 in the same manner as Cr and Cu. If Sn is contained even in a small amount, the above effect can be obtained to some extent. However, if the Sn content exceeds 0.50%, the secondary recrystallization becomes unstable during the manufacturing process of the directional electromagnetic steel plate 1 even if the content of other elements is within the range of the present embodiment. As a result, the magnetic characteristics of the directional electromagnetic steel plate 1 are deteriorated. Therefore, the Sn content is 0 to 0.50%. The lower limit of the Sn content is more than 0%, more preferably 0.01%, still more preferably 0.02%, still more preferably 0.03%.
[0054]
Cu: 0 to 0.50%
Copper (Cu) is a selective element. That is, the Cu content may be 0%. When Cu is contained, Cu enhances the adhesion of the glass coating 11 to the base steel plate 10 in the same manner as Cr and Sn. If even a small amount of Cu is contained, the above effect can be obtained to some extent. However, if the Cu content exceeds 0.50%, the hot workability in the manufacturing process of the directional electromagnetic steel plate 1 is lowered even if the content of other elements is within the range of the present embodiment. Therefore, the Cu content is 0 to 0.50%. The lower limit of the Cu content is more than 0%, more preferably 0.01%, still more preferably 0.03%, still more preferably 0.05%. The preferred upper limit of the Cu content is 0.40%, more preferably 0.30%, still more preferably 0.20%, still more preferably 0.10%.
[0055]
Bi: 0-0.0100%
Bi (bismus) is a selective element. That is, the Bi content may be 0%. When Bi is contained, Bi functions as an inhibitor in the same manner as Se and Sb, and stabilizes secondary recrystallization during the production of the directional electromagnetic steel plate 1. As a result, the magnetic characteristics of the directional electromagnetic steel plate 1 are enhanced. If even a small amount of Bi is contained, the above effect can be obtained to some extent. However, if the Bi content exceeds 0.0100%, the adhesion of the glass coating 11 to the base steel plate 10 is lowered even if the content of other elements is within the range of the present embodiment. Therefore, the Bi content is 0 to 0.0100%. The preferred lower limit of the Bi content is more than 0%, more preferably 0.0010%, still more preferably 0.0020%. The preferred upper limit of the Bi content is 0.0090%, more preferably 0.0070%, still more preferably 0.0050%.
[0056]
Se: 0-0.020%
Selen (Se) is a selective element. That is, the Se content may be 0%. When Se is contained, Se functions as an inhibitor in the same manner as Bi and Sb, and stabilizes secondary recrystallization during the production of the directional electromagnetic steel plate 1. As a result, the magnetic characteristics of the directional electromagnetic steel plate 1 are enhanced. If Se is contained even in a small amount, the above effect can be obtained to some extent. However, if the Se content exceeds 0.020%, the adhesion of the glass coating 11 to the base steel plate 10 is lowered even if the content of other elements is within the range of the present embodiment. Therefore, the Se content is 0 to 0.020%. The preferred lower limit of the Se content is more than 0%, more preferably 0.001%, still more preferably 0.003%, still more preferably 0.005%. The preferred upper limit of the Se content is 0.015%, more preferably 0.010%, still more preferably 0.008%.
[0057]
Sb: 0 to 0.50%
Antimon (Sb) is a selective element. That is, the Sb content may be 0%. When Sb is contained, Sb functions as an inhibitor in the same manner as Bi and Se, and stabilizes secondary recrystallization during the production of the directional electromagnetic steel plate 1. As a result, the magnetic characteristics of the directional electromagnetic steel plate 1 are enhanced. If even a small amount of Sb is contained, the above effect can be obtained to some extent. However, if the Sb content exceeds 0.50%, the adhesion of the glass coating 11 to the base steel plate 10 is lowered even if the content of other elements is within the range of the present embodiment. Therefore, the Sb content is 0 to 0.50%. The preferred lower limit of the Sb content is more than 0%, more preferably 0.01%, still more preferably 0.03%, still more preferably 0.05%. The preferred upper limit of the Sb content is 0.40%, more preferably 0.30%, still more preferably 0.20%, still more preferably 0.10%.
[0058]
Further, in the directional electromagnetic steel plate 1 according to the present embodiment, the average chemical composition described above is Cr: 0.01 to 0.50%, Sn: 0.01 to 0.50%, Cu: 0 in mass%. At least selected from the group consisting of 0.01 to 0.50%, Bi: 0.0010 to 0.0100%, Se: 0.001 to 0.020%, and Sb: 0.01 to 0.50%. It preferably contains one element.
[0059]
Further, as described above, Cr, Sn, and Cu preferably enhance the adhesion of the glass coating 11. Therefore, the above average chemical composition contains at least one element of Cr: 0.01 to 0.50%, Sn: 0.01 to 0.50%, and Cu: 0.01 to 0.50%. May be good. Further, as described above, Bi, Se, and Sb preferably enhance the magnetic properties of the directional electromagnetic steel plate 1. Therefore, the above average chemical composition contains at least one element of Bi: 0.0010 to 0.0100%, Se: 0.001 to 0.020%, and Sb: 0.01 to 0.50%. May be good.
[0060]
[About glass film 11]
The glass coating 11 is formed on the base steel plate 10. The glass coating 11 is mainly composed of forsterite (Mg 2SiO 4). In the directional electromagnetic steel plate according to the present embodiment, in order to confirm the presence of the glass coating 11, X-ray diffraction is performed on the surface from which the tensioning insulating coating 12 has been removed by the above method. , The obtained X-ray diffraction spectrum may be collated with a PDF (Power Diffraction File). For example, JCPDS number: 34-189 may be used for identification of forsterite (Mg 2SiO 4). In the present embodiment, it is determined that the directional electromagnetic steel plate 1 has the glass coating 11 when the main configuration of the X-ray diffraction spectrum is forsterite.
[0061]
For example, the content of forsterite in the glass film 11 may be 60.0% or more in mass%.
[0062]
The thickness of the glass coating 11 is not particularly limited. The preferred lower limit of the thickness of the glass coating 11 is 1.0 μm, more preferably 2.0 μm. The preferred upper limit of the thickness of the glass coating 11 is 5.0 μm, more preferably 4.0 μm.
[0063]
[About the tensioning insulating film 12]
The tensioning insulating film 12 is formed on the glass film 11. When a plurality of directional electromagnetic steel plates 1 are laminated and used, the tension-applied insulating coating 12 is applied to the uppermost layer of the directional electromagnetic steel plates 1 in order to ensure the insulation between the directional electromagnetic steel plates 1 laminated to each other. It is formed.
[0064]
In the directional electromagnetic steel plate according to the present embodiment, in order to confirm the presence of the tension-applied insulating film 12, the uppermost layer of the directional electromagnetic steel plate 1 may be quantitatively analyzed by SEM-EDS to confirm the chemical composition. .. For example, the quantitative analysis result of SEM-EDS shows that Fe content is less than 80 atomic%, P content is 5 atomic% or more, Si content is less than 20 atomic%, and O content is 50 atomic%, excluding measurement noise. % Or more and the Mg content is 10 atomic% or less, it is determined that the directional electromagnetic steel plate 1 has the tension-applied insulating film 12.
[0065]
For example, the tension-applied insulating coating 12 is coated with an insulating coating agent containing at least one of inorganic substances such as a metal chromium acid salt, a metal phosphate salt, colloidal silica, polytetrafluoroethylene, a Zr compound, and a Ti compound. , Formed by baking. The insulating coating agent may be mainly composed of a phosphoric acid compound. For example, the insulating coating agent may have a phosphate compound content of 80% or more in mass%.
[0066]
The insulating coating agent for forming the tension-imparting insulating film 12 may contain one or more selected from the group consisting of colloidal silica and polytetrafluoroethylene together with the phosphoric acid compound. The phosphoric acid compound is, for example, sodium phosphate, aluminum phosphate, magnesium phosphate and the like.
[0067]
The thickness of the tensioning insulating film 12 is not particularly limited. The preferred lower limit of the thickness of the tension-applied insulating coating 12 is 0.1 μm, more preferably 0.5 μm. The preferred upper limit of the thickness of the tension-applied insulating coating 12 is 10.0 μm, more preferably 5.0 μm.
[0068]
[Regarding the degree of localization of spinel (MgAl 2O 4) in the glass film 11]
In the directional electromagnetic steel plate 1 according to the present embodiment, spinel (MgAl 2O 4) is localized in the vicinity of the interface with the base steel plate 10 in the glass coating 11. Specifically, after removing the tension-applied insulating film 12, glow discharge emission analysis is performed in the depth direction from the surface of the glass film 11, and the glow emission spectral spectrum showing the emission intensity of Al and the emission intensity of Si () GDS spectrum of Al, GDS spectrum of Si) is obtained. The surface of the glass coating is defined as the measurement start time Ts, the time when Al becomes the maximum emission intensity in the GDS spectrum of Al is defined as T Al p, and the emission intensity of Al at the time T Al p (that is, the maximum emission of Al). Intensity) is defined as F (T Al p), the time when Si becomes the maximum emission intensity in the GDS spectrum of Si is defined as T Sip, and the emission intensity of Al at the time T Sip (that is, of Si). The emission intensity of Al at the depth position of the maximum emission intensity) is defined as F (TSip). At this time, Ts, T Al p, F (T Al p), T S p, and F (T S p) satisfy the formulas (1) and (2).
0.05 ≤ F (TS i p) / F (T Al p) ≤ 0.50 ... (Equation 1)
2.0 ≤ (T Al p-Ts) / (TS i p-Ts) ≤ 5.0 ... (Equation 2)
[0069]
Hereinafter, equations (1) and (2) will be described.
[0070]
[About formula (1)]
In the directional electromagnetic steel plate 1 according to the present embodiment, the spinel (MgAl 2O 4) is distributed in the glass coating 11 in the thickness direction of the glass coating 11, and the distribution of the spinels is the same as that of the base steel plate 10 in the glass coating 11. It shows a peak near the interface. That is, the GDS spectrum of Al has a peak in the vicinity of the interface with the base steel plate 10 in the glass coating 11. In the directional electromagnetic steel plate 1 according to the present embodiment, the sharper the peak of the GDS spectrum of Al near the interface between the glass coating 11 and the base steel plate 10, the more the spinel is at the interface between the glass coating 11 and the base steel plate 10. It will be localized in.
[0071]
In FIG. 3, Al and Si glows have the surface of the glass coating 11 as the measurement start time Ts, the horizontal axis as the measurement time (unit: seconds), and the vertical axis as the emission intensity (GDS intensity) (unit: arbitry unit). It is a figure which shows the emission spectral spectrum (GDS spectrum of Al and GDS spectrum of Si). Time Ts, time T Al p, emission intensity F (T Al p), time T Ship, and emission intensity F (TS p) shown in FIG. 3 are defined as follows.
[0072]
Measurement start time Ts:
In the glow emission spectral spectrum, the surface of the glass coating 11 is defined as the measurement start time Ts.
[0073]
Time T Al p:
After removing the tensioning insulating film 12 of the directional electromagnetic steel plate 1, glow discharge emission analysis is performed in the depth direction from the surface of the glass film 11, and the surface of the glass film 11 is set as the measurement start time Ts, and the measurement time and Al. The glow emission spectral spectrum of Al (GDS spectrum of Al) showing the relationship with the emission intensity of Al is obtained. Here, the measurement time corresponds to the depth from the surface of the glass coating 11. With respect to the obtained GDS spectrum of Al, the maximum value of the emission intensity and the time of the maximum value are specified. The specified time is defined as time T Al p. That is, the time T Al p corresponds to the depth position (the depth position from the surface of the glass coating 11) at which the Al concentration (GDS intensity of Al) peaks.
[0074]
Emission intensity F (T Al p):
In the glow emission spectral spectrum of Al (GDS spectrum of Al) described above, the maximum value of the emission intensity of Al, that is, the maximum emission intensity of Al at time T Al p is defined as F (T Al p).
[0075]
Time T Sip:
After removing the tensioning insulating film 12 of the directional electromagnetic steel plate 1, glow discharge emission analysis is performed from the surface of the glass film 11 in the depth direction, and the surface of the glass film 11 is set as the measurement start time Ts, and the measurement time and Si. The glow emission spectral spectrum of Si (GDS spectrum of Si) showing the relationship with the emission intensity of Si is obtained. As described above, the measurement time corresponds to the depth from the surface of the glass coating 11. With respect to the GDS spectrum of the obtained Si, the maximum value of the emission intensity and the time of the maximum value are specified. The specified time is defined as the time T Ship. That is, the time TSip corresponds to the depth position (depth position from the surface of the glass coating 11) at which the Si concentration (GDS intensity of Si) peaks.
[0076]
Emission intensity F (TSip):
In the glow emission spectral spectrum of Al (GDS spectrum of Al) described above, the emission intensity of Al corresponding to the time TSip is defined as F (TSip).
[0077]
The main component of the glass coating 11 is forsterite (Mg 2SiO 4). Therefore, the GDS spectrum of Si shows a peak at the center of the glass coating 11 in the depth direction. That is, the time TSip corresponds to the center position of the glass coating 11 in the depth direction. That is, F (TSip) means the Al concentration at the center position in the depth direction of the glass coating 11.
[0078]
Defined as F1 = F (TS i p) / F (T Al p). F1 is the maximum Al concentration (F (T Al p)) in the glass film 11 with respect to the typical Al concentration (F (TS p)) in the region excluding the peak position of the Al concentration in the glass film 11. It shows the ratio and is an index showing the degree of localization of spinel in the glass coating 11.
[0079]
When F1 is less than 0.05, spinel is excessively generated in the vicinity of the interface with the base steel plate 10 in the glass coating 11. The spinel localized near the interface with the base steel plate 10 enhances the film adhesion, but if the localized spinel is excessively large, the smoothness of the interface between the glass film 11 and the base steel plate 10 deteriorates. (That is, there are many irregularities). As a result, even if F2 described later satisfies the equation (2), the magnetic characteristics are deteriorated.
[0080] [0080]
On the other hand, when F1 exceeds 0.50, the spinel exists inside the glass coating 11 instead of near the interface with the base steel plate 10 in the glass coating 11. Alternatively, although spinel is present in the vicinity of the interface with the base steel plate 10 in the glass coating 11, the amount of spinel produced is small. In this case, the film adhesion of the glass film 11 to the base steel plate 10 is lowered.
[0081]
If F1 is 0.05 to 0.50, that is, if F1 satisfies the formula (1), an appropriate amount of spinel is present in the vicinity of the interface with the base steel plate 10 in the glass coating 11. .. Therefore, on the premise that the formula (2) is satisfied, the adhesion of the glass coating 11 to the base steel plate 10 is enhanced.
[0082]
[About formula (2)]
F2 = (T Al p-Ts) / (TS i p-Ts) is defined. As shown in FIG. 3, F2 shows the relationship between the peak position of the Al concentration and the peak position of the Si concentration (that is, the center position in the depth direction of the glass coating 11), and the spinel in the glass coating 11 It is an index showing the localized position of.
[0083]
If F2 is less than 2.0, the peak position of Al concentration is located inside the glass coating 11 rather than near the interface with the base steel plate 10 in the glass coating 11. That is, the spinel is not localized near the interface with the base steel plate 10, but exists inside the glass coating 11. In this case, F1 also exceeds the upper limit of the formula (1), and as a result, the adhesion of the glass coating 11 to the base steel plate 10 is lowered. On the other hand, when F2 exceeds 5.0, the amount of glass film 11 produced is excessively small with respect to the amount of spinel produced. That is, the glass coating 11 is thinned. In this case, even if F1 satisfies the formula (1), the tension of the glass coating 11 required for the subdivision of the magnetic region is reduced. Therefore, the iron loss is reduced and the film adhesion is also reduced.
[0084]
If the spinel is formed in an appropriate amount in the vicinity of the interface with the base steel plate 10 in the glass coating 11, the detailed reason why the adhesion of the glass coating 11 to the base steel plate 10 is enhanced is not clear at this time. However, the following matters can be considered. Fine irregularities are formed on the surface of the base steel plate 10. When the spinel is present in the vicinity of the interface with the base steel plate 10 in the glass coating 11, the spinnel is fitted into the recess on the surface of the base steel plate 10. Therefore, it is considered that the spinel exerts an anchor effect and enhances the adhesion of the glass coating 11 to the base steel plate 10. There is a possibility that the adhesion of the glass coating 11 to the base steel plate 10 is enhanced by a mechanism different from this mechanism. However, if F1 satisfies the formula (1) and F2 satisfies the formula (2), the adhesion of the glass coating 11 to the base steel plate 10 is enhanced, as illustrated in the examples described later.
[0085]
[Calculation method of F1 and F2]
The above-mentioned F1 value and F2 value can be obtained by the following method. First, a sample having a rolling direction RD of 30 mm, a plate width direction TD of 40 mm, and a thickness of the directional electromagnetic steel plate 1 is taken from the central portion of the directional electromagnetic steel plate 1 in the plate width direction TD. The tensioning insulating film 12 is removed from the collected sample. Specifically, the directional electromagnetic steel plate 1 has NaOH: 30 to 50% by mass and H 2O: 50 to 70% by mass.%, Soaked in an aqueous sodium hydroxide solution at 80-90 ° C. for 7-10 minutes. The soaked steel plate (base steel plate 10 provided with the glass coating 11 from which the tensioning insulating coating 12 has been removed) is washed with water. After washing with water, dry it with a warm air blower for a little less than 1 minute. By the above processing, as shown in FIG. 4, a sample having the base steel plate 10 and the glass coating 11 and having the tension-applied insulating coating 12 removed is prepared.
[0086]
Glow discharge emission analysis (GDS: Glow Discharge Spectrum) is performed from the surface of the glass coating 11 of the sample in the depth direction to measure the glow emission spectral spectra of Al and Si (hereinafter referred to as GDS spectra). Specifically, using a high-frequency glow emission spectroscope (GD-ODS), an output of 30 W is applied to the depth of the glass coating 11 under an argon atmosphere (Ar pressure: 3 hPa) using the sample as a cathode. The GDS spectrum of Al and the GDS spectrum of Si in the direction are measured. The measurement area is 4 mmφ, the measurement time is 100 seconds, and the measurement interval is 0.02 seconds.
[0087]
It is preferable that the above calculation of F1 and F2 is performed after smoothing the GDS spectrum after measurement. As a method for smoothing the GDS spectrum, for example, a simple moving average method may be used.
[0088]
From the obtained GDS spectrum of Al, the time T Al p at which Al has the maximum emission intensity and the emission intensity F (T Al p) of Al at the time T Al p are obtained.
[0089]
Further, in the obtained GDS spectrum of Si, the time TSip at which Si has the maximum emission intensity is specified. Then, the emission intensity F (TSip) of Al at the time TSip is obtained from the GDS spectrum of Al. The measurement start time is Ts. Using the obtained time Ts, time T Al p, F (T Al p), time T S p, and F (T S p), F1 and F2 are obtained.
[0090]
In the directional electromagnetic steel plate 1 according to the present embodiment, F1 satisfies the formula (1) and F2 satisfies the formula (2). Therefore, in the glass coating 11, spinels are localized in an appropriate amount in the vicinity of the interface of the base steel plate 10, and the adhesion of the glass coating 11 to the base steel plate 10 is high.
[0091]
When F1 satisfies the formula (1) and F2 satisfies the formula (2), the spinel is localized in the vicinity of the interface between the base steel plate 10 and the glass coating 11 in the glass coating 11. I can judge.
[0092]
Further, whether or not the spinel is localized in the vicinity of the interface between the base steel plate 10 and the glass coating 11 in the glass coating 11 may be determined from the following characteristics.
[0093]
Regarding the glow emission spectral spectra of Al and Fe obtained by performing glow discharge emission analysis in the depth direction from the surface of the glass coating
The time when Al becomes the maximum emission intensity is defined as T Al p,
The time when the Fe emission intensity becomes 60% of the saturation value of the Fe emission intensity is defined as T Fe 60.
When the time when the Fe emission intensity becomes 90% of the saturation value of the Fe emission intensity is defined as T Fe 90,
The T Al p, the T Fe 60, and the T Fe 90 are
T Fe 60 ≤ T Al p ≤ T Fe 90 ... (Equation 3)
All you have to do is meet.
[0094]
In addition to the above formulas (1) and (2), when the above formula (3) is satisfied, the spinel is localized in the vicinity of the interface between the base steel plate 10 and the glass coating 11 in the glass coating 11. It is preferable because it can be judged that it is. The above-mentioned "saturation value of Fe emission intensity" may be, for example, the Fe emission intensity when the measurement time of glow discharge emission analysis is 100 seconds.
[0095]
[Production method]
Hereinafter, an example of the manufacturing method of the directional electromagnetic steel plate 1 according to the present embodiment will be described. The method of manufacturing the directional electromagnetic steel plate 1 according to the present embodiment is not particularly limited as long as it has the above-mentioned configuration. The following manufacturing method is one example for manufacturing the directional electromagnetic steel plate 1 according to the present embodiment, and is a preferable example of the manufacturing method for the directional electromagnetic steel plate 1 according to the present embodiment.
[0096]
[Manufacturing process flow]
FIG. 5 is a flow chart of a method for manufacturing the directional electromagnetic steel plate 1 according to the present embodiment. As shown in FIG. 5, in this manufacturing method, a hot rolling step (S1) in which hot rolling is performed on a slab and a shrinking treatment are performed on a steel plate (hot rolled steel plate) after hot rolling. After the hot-rolled plate annealing step (S2), the cold-rolling step (S3) in which the steel plate after the hot-rolled plate annealing step is cold-rolled one or more times (S30), and after the cold-rolling step. A decarburization and quenching step (S4) in which decarburization and annealing is performed on the steel plate (cold-rolled steel plate) of the above, and a quenching and separating agent application step (S5) in which a shrinking separator is applied to the surface of the steel plate after the decarburization and annealing step. Insulation that forms a tensioning insulating film on the steel plate after the finish annealing step (S6), which performs finish annealing on the steel plate coated with the shrinking separator to form a glass film, and the steel plate after the finish annealing step. It includes a film forming step (S7). Hereinafter, each process S1 to S7 will be described.
[0097]
[Hot rolling process (S1)]
In the hot rolling step (S1), hot rolling is performed on the prepared slab to manufacture a hot-rolled steel plate. The chemical composition of the slab is adjusted so that the average chemical composition of the base steel plate 10 and the glass coating 11 of the directional electromagnetic steel plate 1 becomes the above-mentioned chemical composition. However, the Al content of the slab should be 0.01% by mass or more. If the Al content of the slab is less than 0.01% by mass, spinel is not sufficiently formed in the glass coating 11. Also, the slab is manufactured by a well-known method. For example, it manufactures (melts) molten steel. A slab is manufactured by a continuous casting method using molten steel.
[0098]
The prepared slab is hot-rolled using a hot-rolling machine to manufacture a steel plate (hot-rolled steel plate). First, the steel material is heated. For example, the slab is placed in a well-known heating furnace or a well-known soaking furnace and heated. The preferred heating temperature for the slab is 1100 to 1450 ° C. The preferred lower limit of the heating temperature is 1300 ° C. The preferred upper limit of the heating temperature is 1400 ° C.
[0099]
The heated slab is hot-rolled using a hot-rolling machine to manufacture a steel plate (hot-rolled steel plate). The hot rolling mill includes a rough rolling mill and a finishing rolling mill located downstream of the rough rolling mill. The rough rolling machine includes one or a plurality of rough rolling stands arranged in a row. Each rough rolling stand contains a plurality of rolls arranged one above the other. The rough rolling stand may be a reverse type. When a plurality of rough rolling stands are arranged, the rough rolling machine may be a tandem type or a reverse type. The finish rolling machine is equipped with a line of finish rolling stands. Each finish rolling stand contains multiple rolls arranged one above the other. The heated slab is rolled by a rough rolling machine and then further rolled by a finishing rolling machine to manufacture a hot-rolled steel plate.
[0100]
The plate thickness of the hot-rolled steel plate manufactured by hot rolling is not particularly limited, and can be a known plate thickness. The plate thickness of the hot-rolled steel plate is, for example, 2.0 to 3.0 mm.
[0101]
[Hot-rolled plate annealing process (S2)]
The hot-rolled plate annealing step (S2) is an arbitrary step and does not have to be carried out. When this is carried out, in the hot-rolled plate annealing step (S2), the hot-rolled steel plate manufactured in the hot-rolling step (S1) is subjected to an annealing treatment to obtain a hot-rolled fired steel plate. By carrying out the hot-rolled plate annealing step, recrystallization occurs in the steel plate structure and the magnetic properties are enhanced.
[0102]
It suffices to carry out the hot-rolled plate annealing step (S2) by a well-known method. The heating method of the hot-rolled steel plate is not particularly limited, and a well-known heating method may be adopted. The quenching temperature is, for example, 900 to 1200 ° C., and the holding time at the annealing temperature is, for example, 10 to 300 seconds. When the hot-rolled plate annealing step (S2) is carried out, the hot-rolled steel plate may be pickled after the hot-rolled plate annealing step (S2) and before the cold rolling step (S3). ..
[0103]
[Cold rolling process (S3)]
In the cold rolling step (S3), one or a plurality of cold rollings (S30) are carried out on the manufactured steel plate (hot-rolled steel plate or hot-rolled annealed steel plate). Cold rolling (S30) is carried out using a cold rolling machine. A cold rolling machine is, for example, a tandem rolling machine having a plurality of cold rolling stands arranged in a row, and each cold rolling stand includes a plurality of cold rolling rolls. The cold rolling machine may be one reverse type cold rolling stand.
[0104]
In the cold rolling step (S3), the cold rolling may be carried out only once (S30) or may be carried out a plurality of times (S30). When cold rolling is carried out a plurality of times, cold rolling may be carried out using the above-mentioned cold rolling machine, and then an intermediate annealing treatment for the purpose of softening the steel plate may be carried out. In this case, after the intermediate annealing treatment, the next cold rolling is carried out. That is, an intermediate annealing treatment may be performed during the cold rolling.
[0105]
The conditions of the intermediate annealing treatment to be carried out between the cold rolling and the next cold rolling are sufficient as known conditions. The annealing temperature in the intermediate annealing treatment is, for example, 950 to 1200 ° C., and the holding time at the annealing temperature is 30 to 1800 seconds. After reducing the strain introduced into the steel plate (softening the steel plate) in the cold rolling of the previous stage by the intermediate annealing treatment, the cold rolling of the next stage is carried out.
[0106]
When a plurality of cold rolling steps are carried out without carrying out the intermediate annealing step, it may be difficult to obtain uniform characteristics in the manufactured directional electromagnetic steel plate. On the other hand, when cold rolling is carried out a plurality of times and intermediate annealing treatment is carried out between each cold rolling, the magnetic flux density may be low in the manufactured directional electromagnetic steel plate 1. Therefore, the number of cold rollings and the presence or absence of intermediate annealing treatment are determined according to the characteristics and manufacturing cost required for the directional electromagnetic steel plate 1 to be finally manufactured.
[0107]
In the cold rolling step, as described above, only one cold rolling may be performed.
[0108]
The preferable cumulative cold spreading rate in one or more cold rolling is 80 to 95%. Here, the cumulative cold spread rate (%) is defined as follows.
Cold rolling ratio (%) = [(Thickness of steel plate before the start of the first cold rolling-Thickness of the cold-rolled steel plate after the last cold rolling) / Thickness of the steel plate before the start of the first cold rolling] × 100
[0109]
When only one cold rolling is performed in the cold rolling process, the cold spreading ratio is the cold spreading ratio in the one-time cold rolling. If the cumulative reduction rate is 80% or more, a large number of recrystallized nuclei (goth nuclei) having a goth orientation ({110} <001> orientation) can be obtained. Further, when the cumulative reduction rate is 95% or less, the secondary recrystallization is likely to be stabilized in the finish annealing step (S6) described later. The steel plate produced by the cold rolling process is wound into a coil.
[0110]
The plate thickness of the cold-rolled steel plate (the plate thickness after the cold rolling step (S3)) is usually the plate thickness of the directional electromagnetic steel plate 1 which is the final product (the thickness of the glass coating 11 and the tension-applied insulating coating 12). It is different from the product plate thickness including).
[0111]
In the cold rolling step (S2) described above, an aging process may be carried out in order to further improve the magnetic characteristics. The aging process is an arbitrary process. When carrying out the aging treatment, the aging treatment is carried out during the plurality of cold rolling (S30). Specifically, after performing cold rolling (S30), an aging process is performed. Then, after the aging treatment, the next cold rolling (S30) is carried out. Well-known conditions are sufficient for the aging treatment. For example, in the aging treatment, the steel plate after cold rolling (S30) is heat-treated at a temperature of 100 to 500 ° C. for 60 seconds or longer. In this case, it is finally possible to obtain a good secondary recrystallized structure in which the Goth orientation is accumulated.
[0112]
[Decarburization and quenching process (S4)]
In the decarburization annealing step (S4), the steel plate (cold-rolled steel plate) after the cold rolling step (S3) is subjected to decarburization annealing to develop primary recrystallization.
[0113]
The decarburization and annealing step (S4) includes a temperature rise step (S41), a decarburization step (S42), and a cooling step (S43). Temperature rise step (S41) Then, the steel plate is heated to the decarburization and quenching temperature Ta. In the decarburization step (S42), decarburization and quenching is performed on the steel plate heated to the decarburization and quenching temperature Ta to develop primary recrystallization. In the cooling step (S43), the steel plate after the decarburization step (S42) is cooled by a well-known method. The details of each process will be described below.
[0114]
[Raising step (S41)]
In the temperature raising step, first, the steel plate after the cold rolling step (S3) is charged into the heat treatment furnace. In the heat treatment furnace for decarburization and quenching in the present embodiment, for example, the temperature of the cold-rolled steel plate is raised while being controlled to the decarburization and quenching temperature by high-frequency induction heating or energization heating. The atmosphere during the temperature raising step is a dry nitrogen atmosphere or a dry nitrogen-hydrogen mixed atmosphere in which the oxygen potential (PH2O / PH2) is 0.1 or less. When the oxygen potential in the temperature raising step is more than 0.1, Fe-based oxides are likely to be nucleated. Fe oxide nucleated in the temperature raising step grows and develops during decarburization and quenching. When they are present during finish annealing, they inhibit the development of forsterite (Mg 2SiO 4). Although the cause is unknown, Fe oxide has the effect of suppressing the solid phase reaction between SiO 2 and MgO. As a result, Mg 2SiO 4 is thinned, and it becomes difficult for spinel to be localized in the vicinity of the interface with the base steel plate 10 in the glass coating 11. Specifically, spinel (MgAl 2O 4) will be present in Mg 2SiO 4.
[0115]
Although not particularly limited, the temperature rise rate may be 2000 ° C./sec or less, and the ultimate temperature may be 700 to 1000. The reached temperature is different from the decarburization and quenching temperature Ta in the decarburization step.
[0116]
[Decarburization process (S42)]
In the decarburization step (S42) in the decarburization and quenching step (S4), the steel plate after the temperature raising step (S41) is held at the decarburization and quenching temperature Ta, and the decarburization and quenching is carried out. As a result, primary recrystallization is developed on the steel plate. The atmosphere during the decarburization step is a well-known atmosphere, for example, a wet nitrogen-hydrogen mixed atmosphere containing hydrogen and nitrogen. By carrying out decarburization and annealing, carbon in the steel plate is removed from the steel plate, and primary recrystallization occurs. The manufacturing conditions in the decarburization process are as follows.
[0117]
Decarburization firing temperature Ta: 800-950 ° C
As described above, the decarburization and quenching temperature Ta corresponds to the furnace temperature of the heat treatment furnace that carries out the decarburization and quenching, and corresponds to the temperature of the steel plate during the decarburization and quenching. If the decarburization and quenching temperature Ta is less than 800 ° C., the crystal grains of the steel plate after the development of the primary recrystallization are too small. In this case, the secondary recrystallization is not sufficiently expressed in the finish annealing step (S6). On the other hand, if the decarburization and quenching temperature Ta exceeds 950 ° C., the crystal grains of the steel plate after the development of the primary recrystallization are too large. Also in this case, the secondary recrystallization is not sufficiently expressed in the finish annealing step (S6). When the decarburization and quenching temperature Ta is 800 to 950 ° C., the crystal grains of the steel plate after the primary recrystallization develops have an appropriate size, and the secondary recrystallization is sufficiently developed in the finish annealing step (S6).
[0118]
The holding time at the decarburization quenching temperature Ta in the decarburization step (S42) is not particularly limited. The holding time at the decarburization and quenching temperature Ta is, for example, 15 to 150 seconds.
[0119]
[Cooling process (S43)]
In the cooling step (S43), the steel plate after the decarburization step (S42) is cooled to room temperature by a well-known method. The cooling method may be free cooling or water cooling. Preferably, the steel plate after the decarburization step is allowed to cool. In the decarburization and annealing step (S4) by the above steps, the decarburization and annealing treatment is performed on the steel plate.
[0120]
[Burning separator application step (S5)]
A quenching separator application step (S5) is carried out on the steel plate (decarburized and tempered steel plate) after the decarburization and annealing step (S4). In the quenching separator applying step (S5), the annealing separator is applied to the surface of the steel plate. Specifically, an aqueous slurry containing a shrinking separator is applied to the surface of the steel plate. An aqueous slurry is prepared by adding water to a quenching separator and stirring. The quenching separator contains magnesium oxide (MgO). Preferably, MgO is the main component of the quenching separator. Here, the "main component" means that the MgO content in the quenching separator is 80.0% or more in mass%. The quenching separator may contain a well-known additive in addition to MgO. For example, the quenching separator may contain a Ti compound.
[0121]
In the quenching separator application step (S5), the annealing separator of the aqueous slurry is applied on the surface of the steel plate. A steel plate coated with an annealing separator on the surface is wound into a coil. After forming the steel plate into a coil shape, a finish annealing step (S6) is performed.
[0122]
It should be noted that the baking separation agent of the aqueous slurry may be applied on the surface of the steel plate to form the steel plate into a coil shape, and then the baking treatment may be carried out before the finish baking step (S6) is carried out. In the baking process, the coiled steel plate is placed in a furnace kept at 400 to 1000 ° C. and held (baking treatment). As a result, the quench-separating agent applied on the steel plate dries. The holding time is, for example, 10 to 90 seconds. The finish baking step may be carried out on the coiled steel plate coated with the baking separating agent without carrying out the baking treatment.
[0123]
[Finish baking process (S6)]
A finish annealing step (S6) is carried out on the steel plate after the annealing separation agent application step (S5) to develop secondary recrystallization. In the finish ablation step, a two-step ablation step (low-temperature ablation step (S61) and high-temperature ablation step (S62)) is further carried out to form a glass film 11 mainly composed of forsterite, and in the glass film 11 In, spinel is localized in an appropriate amount near the interface of the base steel plate 10. The two-step baking step (low temperature baking step (S61) and high temperature baking step (S62)) is carried out using a heat treatment furnace. Hereinafter, the low temperature annealing step (S61) and the high temperature annealing step (S62) will be described.
[0124]
[Low temperature annealing process (S61)]
The low temperature baking step (S61) is a step for forming the glass film 11. In the low temperature baking step (S61), first, a coiled steel plate is inserted into a heat treatment furnace to raise the temperature of the steel plate to the low temperature baking temperature T1. The holding time is t1 at the low temperature quenching temperature T1. The atmosphere in the furnace in the low-temperature annealing step (S61) may be a mixed atmosphere of hydrogen and nitrogen.
[0125]
The low-temperature quenching temperature T1 (° C.) and the holding time t1 in the low-temperature annealing step (S61) are as follows.
Low temperature quenching temperature T1: 910-1000 ° C
Retention time at 910 to 1000 ° C. t1: 50 to 120 hours
[0126]
[About low temperature quenching temperature T1]
910 to 1000 ° C. is a temperature range generated by forsterite (Mg 2SiO 4), which is the main component of the glass film 11.
[0127]
When the low temperature quenching temperature T1 is less than 910 ° C., the alumina formation (4Al + 3SiO 2 → 2Al 2O 3 + 3Si) occurs before the forsterite formation (2MgO + SiO 2 → Mg2SiO 4), and as a result, the high temperature baking step (S62). ) Later, spinels are generated inside the glass coating 11 instead of near the interface between the glass coating 11 and the base steel plate 10. As a result, F1 deviates from the upper limit of the equation (1) and / or F2 deviates from the lower limit of the equation (2).
[0128]
If the low temperature annealing temperature T1 exceeds 1000 ° C., the formation of forsterite becomes insufficient and the glass film 11 becomes thin. Therefore, although F1 satisfies the equation (1), it exceeds the upper limit of the equation (2). As a result, the tension of the glass coating 11 required for subdividing the magnetic region is reduced. Therefore, the iron loss is reduced and the film adhesion is also reduced.
[0129]
[Retention time t1 at low temperature quenching temperature T1]
If the low-temperature quenching temperature T1 is appropriate, that is, if the low-temperature annealing temperature T1 is 910 to 1000 ° C. and the holding time t1 at the low-temperature annealing temperature T1 is less than 50 hours, the generation of forsterite becomes insufficient. , The glass coating 11 becomes thin. Therefore, although F1 satisfies the equation (1), F2 exceeds the upper limit of the equation (2). As a result, the insulating property is lowered.
[0130]
When the low temperature annealing temperature T1 is appropriate and the holding time t1 exceeds 120 hours, forsterite is excessively generated and Mg is consumed by forsterite. In this case, the amount of Mg that can be used to generate the spinel (MgAl 2O 3) is insufficient, and the production of the spinel is insufficient. As a result, although F2 satisfies the equation (2), F1 exceeds the upper limit of the equation (1).
[0131]
Therefore, when the low temperature baking temperature T1 is appropriate, that is, the holding time t1 at the low temperature baking temperature T1 is 50 to 120 hours.
[0132]
If the low-temperature quenching temperature T1 is 910 to 1000 ° C. and the holding time t1 at the low-temperature annealing temperature T1 is 50 to 120 hours, forsterite is sufficiently formed and grown, and the glass film 11 is sufficiently thickened. As a result, on the premise that the conditions in the high-temperature annealing step (S62) described later are satisfied, the spinel is localized in the vicinity of the interface of the base steel plate 10 in the glass coating 11, and F1 satisfies the formula (1). , F2 satisfy equation (2).
[0133]
In the low temperature annealing step (S61), it is sufficient to maintain the range of 910 to 1000 ° C. with the holding time t1. That is, if the holding time t1 in the temperature range of 910 to 1000 ° C. is set to 50 to 120 hours, the temperature during the holding time t1 may be constant, or the temperature may be raised or lowered.
[0134]
[High temperature annealing process (S62)]
The high temperature baking step (S62) is a step for forming spinels in the glass coating 11 generated in the low temperature baking step (S61) and localizing the spinels in the vicinity of the interface of the base steel plate 10. Specifically, after the low temperature baking step (S61) is completed, the temperature of the steel plate is further raised to the high temperature baking temperature T2. The rate of temperature rise is not particularly limited. After that, the holding time is t2 at the high temperature annealing temperature T2 shown below. The high temperature baking step may be carried out in the same heat treatment furnace as the low temperature baking step, or may be carried out in a different heat treatment furnace. The atmosphere in the furnace in the high-temperature annealing step may be a nitrogen atmosphere.
[0135]
The high temperature quenching temperature T2 (° C.) and the holding time t2 (hours) at T2 are as follows.
High temperature quenching temperature T2: 1100 ~ 1300 ℃
Holding time at high temperature quenching temperature T2 t2: 20-80 hours
[0136]
[About high temperature quenching temperature T2]
1100 to 1300 ° C is the spinnel formation temperature range. The glass film 11 is sufficiently formed by the low temperature baking step. Therefore, if it is held in the temperature range of 1100 to 1300 ° C. in the high-temperature annealing step, Al contained in the base steel plate 10 moves to the vicinity of the interface between the glass coating 11 and the base steel plate 10 and reacts with forsterite. To form a spinel. As a result, during the high-temperature baking step, a spinel is formed in the vicinity of the interface with the base steel plate 10 in the glass coating 11, and the spinel is localized in the vicinity of the interface.
[0137]
If the high temperature annealing temperature T2 is less than 1100 ° C, spinnel is not sufficiently produced. In this case, F2 satisfies the equation (2), but F1 exceeds the upper limit of the equation (1).
[0138]
If the high temperature annealing temperature T2 exceeds 1300 ° C., spinels are excessively generated, and although F2 satisfies the formula (2), F1 is less than the lower limit of the formula (1).
[0139]
Therefore, the high temperature annealing temperature T2 is 1100 to 1300 ° C.
[0140]
[Retention time t2 at 1100-1300 ° C]
If the holding time t2 at 1100 to 1300 ° C. is less than 20 hours, spinel will not be sufficiently produced. In this case, F2 satisfies the equation (2), but F1 exceeds the upper limit of the equation (1).
[0141]
If the holding time t2 at 1100 to 1300 ° C. exceeds 80 hours, spinels are excessively generated, and F2 satisfies the formula (2), but F1 is less than the lower limit of the formula (1).
[0142]
Therefore, the holding time t2 at 1100 to 1300 ° C. is 20 to 80 hours.
[0143]
If the high-temperature baking temperature T2 is 1100 to 1300 ° C. and the holding time t2 at the high-temperature baking temperature T2 is 20 to 80 hours, the glass coating 11 has sufficient spinel near the interface with the base steel plate 10. Spinel stationed near the interface Incorporate. Therefore, F1 satisfies the equation (1) and F2 satisfies the equation (2).
[0144]
In the high-temperature annealing step (S62), the high-temperature annealing temperature T2 may be kept constant and the holding time t2 may be held, or the holding time t2 may be held while baking in the range of 1100 to 1300 ° C. If the holding time t2 in the temperature range of 1100 to 1300 ° C. is set to 20 to 80 hours, the temperature during the holding time t2 may be constant, or may be raised or lowered.
[0145]
Preferably, the purification annealing step may be carried out after the high temperature baking step (S62) and before the insulating film forming step (S7). If a purification and annealing step is carried out, the magnetism will be further improved. In the purification annealing step, the annealing temperature is 1000 to 1300 ° C. and the holding time is 10 hours or more under a hydrogen atmosphere. By the purification and annealing step, each element of the chemical composition of the base steel plate 10 is removed from the components in the steel to some extent. In particular, residual elements such as S, Al, and N that affect iron loss are largely removed.
[0146]
[Insulation film forming step (S7)]
In the method for manufacturing the directional electromagnetic steel plate 1 according to the present embodiment, the insulating film forming step (S7) is further carried out after the finish annealing step (S6). In the insulating film forming step (S7), an insulating coating agent mainly composed of colloidal silica and phosphate is applied to the surface (on the glass film 11) of the directional electromagnetic steel plate 1 after cooling in the finish annealing step (S6). After that, baking is carried out. As a result, the tension-applied insulating film 12 is formed on the glass film.
[0147]
Here, the tension applying insulating film 12 formed on the surface of the steel plate is not particularly limited as long as it is used as the tension applying insulating film of the directional electromagnetic steel plate 1, and a known tension applying insulating film can be used. It can be used. Examples of such a tension-applied insulating film include a composite insulating film mainly composed of an inorganic substance and further containing an organic substance. Here, the composite insulating film is mainly composed of at least one of an inorganic substance such as a metal chromium acid salt, a metal phosphate salt or a colloidal silica, a Zr compound, and a Ti compound, and fine organic resin particles are dispersed. It is an insulating film. In particular, a tension-applied insulating film using a metal phosphate metal salt, a Zr, Ti coupling agent, or a carbonate or ammonium salt thereof is preferable. Further, following the insulating film forming step (S7), flattening and annealing for shape correction may be performed. By flattening and annealing the steel plate, iron loss can be further reduced.
[0148]
In the directional electromagnetic steel plate 1 manufactured by the above manufacturing process, F1 satisfies the formula (1), F2 satisfies the formula (2), and the spinel in the vicinity of the interface with the base steel plate 10 in the glass coating 11 Can be localized. As a result, the adhesion of the glass coating 11 to the base steel plate 10 is improved.
[0149]
In particular, in the above manufacturing method, in order to manufacture the directional electromagnetic steel plate 1 according to the present embodiment, the Al content of the slab used in the hot rolling step (S1) is set to 0.01% by mass or more, and decarburization and quenching is performed. In the temperature raising step (S41) of the step (S4), the oxygen potential (PH2O / PH2) is set to 0.1 or less, and in the low temperature baking step (S61) and the high temperature baking step (S62) of the finish baking step (S6). It is important to control the annealing conditions.
[0150]
[Other manufacturing processes]
The directional electromagnetic steel plate 1 according to the present embodiment may be subjected to a nitriding treatment step after the decarburization annealing step (S4) and before the annealing separation agent application step (S5). In the nitriding treatment step, the steel plate after the decarburization and annealing step (S4) is subjected to a nitriding treatment to manufacture a nitriding steel plate. It suffices to carry out the nitriding process under well-known conditions. Preferred nitriding conditions are, for example:
[0151]
Nitride treatment temperature: 700-850 ° C
Atmosphere in the nitriding furnace (nitriding atmosphere): An atmosphere containing a gas having a nitriding ability such as hydrogen, nitrogen and ammonia.
[0152]
If the nitriding treatment temperature is 700 ° C. or higher, or the nitriding treatment temperature is less than 850 ° C., nitrogen easily penetrates into the steel plate during the nitriding treatment. In this case, the amount of nitrogen inside the steel plate becomes sufficient in the nitriding process. Therefore, a fine AlN immediately before the secondary recrystallization can be sufficiently obtained. As a result, secondary recrystallization is sufficiently expressed in the finish annealing step (S6). The holding time at the nitriding treatment temperature in the nitriding treatment step is not particularly limited, but is, for example, 10 to 60 seconds.
[0153]
[Magnetic zone subdivision processing process]
The directional electromagnetic steel plate 1 according to the present embodiment may further be subjected to a magnetic group subdivision treatment step after the finish annealing step (S6) or the insulating film forming step (S7), if necessary. In the magnetic group subdivision processing step, the surface of the directional electromagnetic steel plate 1 is irradiated with a laser beam having a magnetic area subdivision effect, or a groove is formed on the surface. In this case, the directional electromagnetic steel plate 1 having further excellent magnetic characteristics can be manufactured.
Example 1
[0154]
Next, the effect of one aspect of the present invention will be described in more detail by way of examples, but the conditions in the examples are one condition example adopted for confirming the feasibility and effect of the present invention. However, the present invention is not limited to this one-condition example. The present invention can adopt various conditions as long as the gist of the present invention is not deviated and the object of the present invention is achieved.
[0155]
[Manufacturing of directional electromagnetic steel sheets with each test number]
As a basic chemical composition, in mass%, C: 0.03 to 0.10%, Si: 3.0 to 3.5%, sol. Al: 0.2 to 0.3%, Mn: 0.02 to 0.90%, N: 0.005 to 0.03%, S: 0.005 to 0.03%, P: 0.005 to A slab containing 0.03% and having Fe and impurities in the balance was produced.
[0156]
A hot rolling process was carried out on the above slab. Specifically, after heating the slab to 1350 ° C., hot rolling was performed on the slab to produce a hot-rolled steel plate having a plate thickness of 2.3 mm. A hot-rolled plate baking step was carried out on the hot-rolled steel plate after the hot-rolling step at a shrinking temperature of 900 to 1200 ° C. and a holding time of 10 to 300 seconds. Then, a cold rolling step was carried out to produce a cold-rolled steel plate (base steel plate) having a plate thickness of 0.19 to 0.23 mm.
[0157]
A decarburization and annealing process was carried out on the cold-rolled steel plate. In the decarburization and quenching step, the decarburization and quenching temperature Ta was set to 800 to 950 ° C., and the decarburization and quenching temperature Ta was maintained for 100 seconds. After the decarburization and annealing step, a baking separation agent containing magnesium oxide (MgO) as a main component and a Ti compound as required was applied to the surface of the steel plate to carry out a finish baking step.
[0158]
Directional after cooling in the finish baking step The surface of the electromagnetic steel plate (on the glass film) was coated with an insulating coating agent mainly composed of colloidal silica and a metal phosphate salt, and then baked. Through the above steps, directional electromagnetic steel sheets with each test number were manufactured.
[0159]
Detailed manufacturing conditions and manufacturing results are shown in Tables 1 to 6. "-" In the table indicates that the chemical composition is not controlled and manufactured in consideration of the content, and the content is not measured, and the manufacturing conditions and evaluation results are controlled. Or it indicates that the evaluation has not been carried out.
[0160]
As shown in Tables 4 to 6, in Test Nos. 1 to 56, 58, 59, and 63 to 66, both the low temperature baking step and the high temperature baking step were carried out in the finish baking step. On the other hand, in test numbers 57 and 60 to 62, although the high temperature annealing step was carried out, the low temperature baking step was not carried out.
[0161]
Further, as shown in Tables 4 to 6, in Test Nos. 1 to 59 and 61 to 66, the temperature of the cold-rolled steel plate was controlled in the temperature raising step of the decarburization and quenching step to raise the temperature. On the other hand, in test number 60, the heat treatment furnace for the decarburization step (S42) is used without carrying out the temperature rise step (S41) of the decarburization annealing step (without controlling the temperature rise condition of the cold-rolled steel plate). A cold-rolled steel plate was put in and heated to the decarburization and quenching temperature Ta.
[0162]
Although not shown in the table, in test numbers 1 to 62, 65, and 66, the Al content of the slab was 0.01% by mass or more. On the other hand, in test numbers 63 and 64, the Al content of the slab was less than 0.01% by mass.
[0163]
The following evaluation was carried out for the directional electromagnetic steel plate manufactured by the above manufacturing method.
[0164]
[Chemical composition analysis of the base steel plate with a glass coating after removing the tensioning insulating coating among the directional electromagnetic steel plates]
Of the directional electromagnetic steel plates of each test number, the chemical composition of the base steel plate with the glass coating (average chemical composition of the base steel plate and the glass coating) after removing the tension-applied insulating film is analyzed by the following method. did.
[0165]
First, the tensioning insulating film was removed from the directional electromagnetic steel plate by the above method. Specifically, the directional electromagnetic steel plate was immersed in an aqueous sodium hydroxide solution at 80 to 90 ° C. for 7 to 10 minutes, containing NaOH: 30 to 50% by mass and H 2O: 50 to 70% by mass. The soaked steel plate (base steel plate with a glass coating from which the tensioning insulating film was removed) was washed with water. After washing with water, it was dried with a warm air blower for a little less than 1 minute. By the above treatment, the tensioning insulating film was removed, and a base steel plate having a glass film was obtained.
[0166]
A well-known component analysis method was carried out on the base steel plate having a glass film after the tension-applied insulating film was removed. Specifically, a drill was used to generate chips from a base steel plate having a glass coating, and the chips were collected. The collected chips were dissolved in acid to obtain a solution. ICP-AES was performed on the solution to perform elemental analysis of the chemical composition.
[0167]
Si in the chemical composition of the base steel plate having a glass coating was determined by the method specified in JIS G1212 (1997) (the method for quantifying silica). Specifically, when the above-mentioned chips are dissolved in an acid, silicon oxide precipitates as a precipitate. This precipitate (silicon oxide) was filtered out with a filter paper, and the mass was measured to determine the Si content.
[0168]
The C content and S content were determined by a well-known high-frequency combustion method (combustion-infrared absorption method). Specifically, the above-mentioned solution was burned in an oxygen stream by high-frequency induction heating, and the generated carbon dioxide and sulfur dioxide were detected, and the C content and the S content were determined.
[0169]
The N content was determined using the well-known inert gas melting-heat conductivity method. The O content was determined using a well-known inert gas melting-non-dispersive infrared absorption method.
[0170]
Tables 1 to 3 show the chemical composition of the base steel plate having the glass coating obtained by the above analysis method (the average chemical composition of the base steel plate and the glass coating).
[0171]
[F1 value measurement test]
Samples of 30 mm in the rolling direction RD, 40 mm in the plate width direction TD, and the plate thickness of the directional electromagnetic steel plate in the thickness were taken from the central portion of the TD in the plate width direction of the directional electromagnetic steel plate of each test number. The tensioning insulating film was removed from the sample taken. Specifically, the directional electromagnetic steel plate was immersed in an aqueous sodium hydroxide solution at 80 to 90 ° C. for 7 to 10 minutes, containing NaOH: 30 to 50% by mass and H 2O: 50 to 70% by mass. The directional electromagnetic steel plate after immersion was washed with water, and then dried with a warm air blower for a little less than 1 minute. By the above method, a sample was prepared in which the base steel plate and the glass coating were provided and the tensioning insulating coating was removed.
[0172]
Glow discharge emission analysis was performed in the depth direction from the surface of the glass coating of the sample, and the GDS spectra of Al, Si, and Fe were measured. Specifically, using a high-frequency glow emission spectroscope (GD-ODS, manufactured by Rigaku, GDA750), an output of 30 W is applied to the glass under an argon atmosphere (Ar pressure: 3 hPa) using the sample as a cathode. The GDS spectrum of Al, the GDS spectrum of Si, and the GDS spectrum of Fe in the depth direction of the coating film were measured. The measurement area was 4 mmφ, the measurement time was 100 seconds, and the measurement interval was 0.02 seconds.
[0173]
The obtained GDS spectrum was smoothed by the simple moving averaging method.
[0174]
Using the obtained GDS spectrum of Al, the time T Al p and F (T Al p) were determined. Similarly, the time TSip is obtained using the obtained GDS spectrum of Si., Al emission intensity F (TSip) at time TSip was determined using the GDS spectrum of Al. The measurement start time was Ts. F1 and F2 were determined using the obtained time Ts, time T Al p, emission intensity F (T Al p), time T Ship, and emission intensity F (TS p). The obtained F1 and F2 values ​​are shown in Tables 4 to 6.
[0175]
Although not shown in the table, the time T Fe 60 and the time T Fe 90 were also obtained using the obtained GDS spectrum of Fe.
[0176]
[Measurement of magnetic flux density B8 and iron loss W 17/50]
A sample with a width of 60 mm and a length of 300 mm was taken, including the center position of the plate width of the directional electromagnetic steel plate of each test number. The length of the sample was parallel to the rolling direction. Using the collected sample, the magnetic flux density B8 (T) was determined by a single plate magnetic characteristic test (SST test) in accordance with JIS C2556 (2011). Specifically, a magnetic field of 800 A / m was applied to the sample to determine the magnetic flux density (T). The measurement results are shown in Tables 4 to 6. When the magnetic flux density B8 was 1.90 T or more, it was judged to be acceptable.
[0177]
Furthermore, using the above sample, iron loss W 17/50 (W / kg) was measured when the frequency was 50 Hz and the maximum magnetic flux density was 1.7 T in accordance with JIS C2556 (2011). The measurement results are shown in Tables 4 to 6. When the iron loss W 17/50 was less than 0.85 W / kg, it was judged to be acceptable.
[0178]
[Glass film adhesion evaluation test]
A sample of 80 mm in the rolling direction x 30 mm in the plate width direction was taken from the center position of the plate width of the directional electromagnetic steel plate of each test number. The collected sample was wound around a cylinder having a diameter of 20 mm and bent 180 °. After that, the bent sample was returned to the original flat state. After returning to a flat state, the total area of ​​the glass coating remaining without peeling was determined. Using the total area of ​​the obtained glass film, the residual rate of the glass film (area%) was obtained by the following formula.
Glass film residual rate (area%) = total area of ​​glass film remaining without peeling / total area of ​​sample (80 mm x 30 mm) x 100
[0179]
The adhesion of the glass film was evaluated as follows according to the obtained residual rate of the glass film.
Very Good (excellent): 90% or more of the residual area ratio of the film
Good (slightly superior): The film residual area ratio is 85% or more and less than 90%.
Fair (effective): The residual area ratio of the film is 80% or more and less than 85%.
No Good (no effect): The residual area ratio of the film is less than 80%
The evaluation results are shown in Tables 4 to 6. In addition, when the residual rate of the glass film film was Very Good, Good, and Fair, it was judged to be acceptable.
[0180]
For test numbers with a magnetic flux density B8 of less than 1.90T or an iron loss W 17/50 of 0.85 or more, the magnetic characteristics were rejected and the film adhesion evaluation test was not performed.
[0181]
[Evaluation results]
As shown in Tables 1 to 6, the average chemical composition of Test Nos. 1 to 50 was appropriate, and the production conditions were also appropriate. As a result, it was excellent in magnetic properties and glass film adhesion. Although not shown in the table, in test numbers 1 to 50, the GDS spectrum satisfied T Fe 60 ≤ T Al p ≤ T Fe 90 (T Si p ≤ T Al p ≤ T Fe 90). rice field).
[0182]
Of the test numbers 1 to 50, the test numbers 18 to 25 and 39 to 50 have a lower F1 than the test numbers 1 to 17 and 26 to 38, and are within the range of 0.05 to 0.30. there were. As a result, the evaluations of the glass film adhesion evaluation tests of test numbers 18 to 25 and 39 to 50 were all G or VG, which were better than the evaluation results (F) of test numbers 1 to 17 and 26 to 38. rice field.
[0183]
Further, among the test numbers 18 to 25 and 39 to 50, the F1 of the test numbers 22 to 25 and 44 to 50 is in the range of 0.05 to 0.12, and the F1 of the test numbers 18 to 21 and 39 to 43. Was in the range of 0.13 to 0.30. As a result, the evaluations of the glass film adhesion evaluation tests of test numbers 22 to 25 and 44 to 50 were all VG, which were better than the evaluation results (G) of test numbers 18 to 21 and 39 to 43.
[0184]
On the other hand, in test numbers 51 to 66, either the average chemical composition or the production conditions were not preferable. As a result, the magnetic properties and / or the adhesion of the glass film film were not satisfied.
[0185]
In test number 51, the holding time t1 at the low temperature baking temperature T1 (= 910 to 1000 ° C.) was too short in the low temperature baking step of the finish baking step. Therefore, although F1 satisfied the equation (1), F2 exceeded the upper limit of the equation (2). As a result, the iron loss W 17/50 was 0.85 or more, and the magnetic characteristics were low.
[0186]
In test number 52, the holding time t1 at the low temperature baking temperature T1 (= 910 to 1000 ° C.) was too long in the low temperature baking step of the finish baking step. Therefore, although F2 satisfies the equation (2), F1 exceeds the upper limit of the equation (1). As a result, the adhesion to the glass coating was No Good, and the adhesion of the glass coating to the base steel plate was low.
[0187]
In test number 53, the high temperature baking temperature T2 was too low in the high temperature baking step of the finish baking step. Therefore, although F2 satisfies the equation (2), F1 exceeds the upper limit of the equation (1). As a result, the adhesion to the glass coating was No Good, and the adhesion of the glass coating to the base steel plate was low.
[0188]
In test number 54, the high temperature baking temperature T2 was too high in the high temperature baking step of the finish baking step. Therefore, F1 is less than the lower limit of the equation (1). As a result, the iron loss W 17/50 was 0.85 or more, and the magnetic characteristics were low.
[0189]
In test number 55, the holding time t2 at the high temperature baking temperature T2 (= 1100-1300 ° C.) was too short. Therefore, F1 exceeds the upper limit of the equation (1). As a result, all of them were NG in the glass film adhesion evaluation test, and the adhesion of the glass film to the base steel plate was low.
[0190]
In test number 56, the holding time t2 at the high temperature baking temperature T2 (= 1100-1300 ° C.) was too long. Therefore, F1 is less than the lower limit of the equation (1). As a result, the iron loss W 17/50 was 0.85 or more, and the magnetic characteristics were low.
[0191]
In test number 57, the low temperature annealing step was not carried out. Therefore, although F1 satisfied the equation (1), F2 exceeded the upper limit of the equation (2). As a result, the iron loss W 17/50 was 0.85 or more, and the magnetic characteristics were low.
[0192]
In test number 58, the low temperature quenching temperature T1 in the low temperature annealing step was too low. Therefore, F1 exceeds the upper limit of the equation (1), and F2 becomes less than the lower limit of the equation (2). As a result, the magnetic flux density B8 was less than 1.90 T, the iron loss W 17/50 was 0.85 or more, and the magnetic characteristics were low.
[0193]
In test number 59, the low temperature quenching temperature T1 in the low temperature annealing step was too high. Therefore, although F1 satisfied the equation (1), F2 exceeded the upper limit of the equation (2). As a result, the iron loss W 17/50 was 0.85 or more, and the magnetic characteristics were low.
[0194]
In test number 60, the temperature rise step of the decarburization and quenching step was not carried out (the temperature rise condition of the cold-rolled steel plate was not controlled). As a result, the iron loss W 17/50 was 0.85 or more, and the magnetic characteristics were low.
[0195]
In test number 61, the oxygen potential (PH2O / PH2) was more than 0.1 in the temperature raising step of the decarburization and quenching step. As a result, the magnetic flux density B8 was less than 1.90 T, the iron loss W 17/50 was 0.85 or more, and the magnetic characteristics were low.
[0196]
In test number 62, the oxygen potential (PH2O / PH2) was more than 0.1 in the temperature raising step of the decarburization and quenching step. As a result, the magnetic flux density B8 was less than 1.90 T, the iron loss W 17/50 was 0.85 or more, and the magnetic characteristics were low.
[0197]
In test number 63, the oxygen potential (PH2O / PH2) in the temperature raising step of the decarburization annealing step is more than 0.1, the low temperature baking temperature T1 in the low temperature baking step is too low, and the holding in the high temperature baking step. Time t2 was too short. Further, since the Al content of the slab was less than 0.01% by mass, the average chemical composition of the base steel plate and the glass coating of the directional electromagnetic steel plate was insol. The Al content was less than 0.005% by mass. As a result, the magnetic flux density B8 was less than 1.90 T, the iron loss W 17/50 was 0.85 or more, and the magnetic characteristics were low.
[0198]
In test number 64, the oxygen potential (PH2O / PH2) in the temperature raising step of the decarburization annealing step is more than 0.1, the low temperature baking temperature T1 in the low temperature baking step is too low, and the holding in the high temperature baking step. Time t2 was too short. Further, since the Al content of the slab was less than 0.01% by mass, the average chemical composition of the base steel plate and the glass coating of the directional electromagnetic steel plate was insol. The Al content was less than 0.005% by mass. As a result, the magnetic flux density B8 was less than 1.90 T, the iron loss W 17/50 was 0.85 or more, and the magnetic characteristics were low.
[0199]
In test number 65, the oxygen potential (PH2O / PH2) was more than 0.1 in the temperature raising step of the decarburization and quenching step. As a result, the iron loss W 17/50 was 0.85 or more, and the magnetic characteristics were low.
[0200]
In test number 66, the low temperature quenching temperature T1 in the low temperature annealing step was too low. As a result, the magnetic flux density B8 was less than 1.90 T, the iron loss W 17/50 was 0.85 or more, and the magnetic characteristics were low.
[0201]
[table 1]

[0202]
[Table 2]

[0203]
[Table 3]

[0204]
[Table 4]

[0205]
[Table 5]

[0206]
[Table 6]

Industrial availability
[0207]
According to the above aspect of the present invention, it is possible to provide a directional electromagnetic steel plate having excellent adhesion of the glass coating. Therefore, it has high industrial utility.
Description of the sign
[0208]
1 Directional electromagnetic steel plate
10 Base steel plate
11 Glass coating
12 Tension-applied insulating film
The scope of the claims
[Claim 1]
Base steel plate and
The glass coating placed on the base steel plate and
With a tension-applying insulating film arranged on the glass film,
The average chemical composition of the base steel plate and the glass coating is% by mass.
C: 0.010% or less,
Si: 2.5-4.0%,
Mn: 0.01-1.00%,
N: 0.010% or less,
Sol. Al: 0.010% or less,
Insol. Al: 0.005 to 0.030%,
Mg: 0.05 to 0.20%,
O: 0.05 to 0.40%,
Ti: 0 to 0.020%,
S: 0.010% or less,
P: 0.030% or less,
Sn: 0 to 0.50%,
Cr: 0 to 0.50%,
Cu: 0 to 0.50%,
Bi: 0-0.0100%,
Se: 0-0.020%,
Sb: 0 to 0.50% and
The rest consists of Fe and impurities
Regarding the glow emission spectral spectra of Al and Si obtained by performing glow discharge emission analysis in the depth direction from the surface of the glass coating.
The surface of the glass coating was set as the measurement start time Ts.
The time when Al becomes the maximum emission intensity is defined as T Al p,
The emission intensity of Al at the T Al p is defined as F (T Al p).
The time when Si becomes the maximum emission intensity is defined as TSip,
When the emission intensity of Al in the T Ship is defined as F (T Ship),
The Ts, the T Al p, the F (T Al p), the T S p, and the F (T S p)
0.05 ≤ F (TS i p) / F (T Al p) ≤ 0.50, and
2.0 ≤ (T Al p-Ts) / (TS i p-Ts) ≤ 5.0
Meet, directional electromagnetic steel plate.
[Claim 2]
The directional electromagnetic steel plate according to claim 1, wherein the base steel plate has a thickness of 0.17 mm or more and less than 0.22 mm.
[Claim 3]
As the average chemical composition, in mass%,
Cr: 0.01-0.50%,
Sn: 0.01-0.50%,
Cu: 0.0 1 to 0.50%,
Bi: 0.0010-0.0100%,
Se: 0.001 to 0.020%, and
Sb: 0.01-0.50%,
The directional electromagnetic steel plate according to claim 1 or 2, which contains at least one element selected from the group consisting of.
[Claim 4]
Regarding the glow emission spectral spectra of Al and Fe obtained by performing glow discharge emission analysis in the depth direction from the surface of the glass coating.
The time when Al becomes the maximum emission intensity is defined as T Al p,
The time when the Fe emission intensity becomes 60% of the saturation value of the Fe emission intensity is defined as T Fe 60.
When the time when the Fe emission intensity becomes 90% of the saturation value of the Fe emission intensity is defined as T Fe 90,
The T Al p, the T Fe 60, and the T Fe 90 are
T Fe 60 ≤ T Al p ≤ T Fe 90
The directional electromagnetic steel plate according to any one of claims 1 to 3, which satisfies the above conditions.