Technical field
[0001]
The present invention relates to decarburizing the steel sheet to be used for grain oriented electrical steel sheet and its production.
Background technique
[0002]
For example oriented electrical steel sheet used for iron core materials of transformers, etc., contained about 1.8 wt% to 7 wt% of Si, highly are integrated the orientation of the crystal grains of the product in {110} <001> orientation It was a steel plate. Control of the crystal orientation is accomplished by utilizing a catastrophic grain growth phenomenon called secondary recrystallization. Typical methods for controlling this secondary recrystallization, before hot rolling by heating the billet to a temperature higher than 1280 ° C., once a solid solution precipitates such as AlN, hot rolling and then in the annealing process, there is a method for re-precipitated as fine precipitates called inhibitors. In the production of such grain-oriented electrical steel sheet, in order to obtain a steel sheet having superior magnetic properties, but have been made many developments, as further enhanced demands for recent energy saving, further reduction iron loss is demanded. There are various ways in order to reduce iron loss of a grain-oriented electrical steel sheet, a method of reducing the hysteresis loss and high magnetic flux density is effective. In order to improve the magnetic flux density oriented electrical steel sheet, it is important to highly integrated orientations of the crystal grains in the product in {110} <001> orientation. The orientation of the crystal grains in the product {110} in order to highly integrated in the <001> orientation, various techniques have been proposed for the chemical composition of the slab used in the grain-oriented electrical steel sheet and its production.
[0003]
　On the other hand, in the final stage in the manufacture of grain-oriented electrical steel sheet, after wound into a coil by annealing separator is then applied to the steel sheet drying mainly composed of MgO, final finish annealing is performed. At this time, SiO, which is formed during the MgO and decarburization annealing 2 by reaction with principal film, forsterite (Mg 2 SiO 4 primary film composed mainly of) Therefore, in order to take advantage of the method of improving the magnetic flux density as described above on an industrial scale, in addition to the magnetic properties are good, it is important that a good stable even with respect to adhesion of the primary coating is there.
[0004]
　Previously various techniques have been proposed, and good magnetic properties, compatibility between adhesion and excellent primary coating and the steel sheet is difficult.
CITATION
Patent Document
[0005]
Patent Document 1: JP-A-6-88171 Patent Publication
Patent Document 2: JP-A 8-269552 Patent Publication
Patent Document 3: JP 2005-290446 Patent Publication
Patent Document 4: JP 2008-127634 Patent Publication
Patent Document 5: JP 2012-214902 JP
Patent Document 6: JP 2011-68968 JP
Patent Document 7: JP-A 10-8133 discloses
Patent Document 8: JP-A 7-48674 Patent Publication
Summary of the Invention
Problems that the Invention is to Solve
[0006]
　The present invention aims at providing a decarburizing steel sheet used for the superior oriented electrical steel sheet and its production in the adhesion between the primary coating and the steel sheet magnetic properties good.
Means for Solving the Problems
[0007]
　The present inventors have conducted extensive studies to solve the above problems. Result of extensive studies, when certain elements and Cu with Bi or the like on the steel sheet is contained, although excellent magnetic characteristics can be obtained, it was found that sufficient adhesion of the primary coating can not be obtained . Accordingly, the present inventors have conducted further extensive studies the effects of Cu on the adhesion of the primary coating. As a result, it contains the specific elements and Cu described above, good steel sheet adhesion to the primary coating was found to correlate with Cu concentration at the interface region between the primary coating and the steel sheet.
[0008]
　The present inventors have found that further intensive studies based on these findings, and conceived to aspects of the invention described below.
[0009]
　(1)
　in
　mass%,
　Si: 1.8% ~ 7.0%, Cu: 0.03% ~ 0.60%, and
　balance: Fe and impurities,
　have in a chemical composition represented,
　the steel plate comprising a primary film containing forsterite on the surface,
　the grain-oriented electrical steel sheet, wherein the Cu / Fe emission intensity ratio at the interface region between the primary coating and the surface of the steel sheet is 0.30 or less.
[0010]
　(2)
　in
　mass%,
　C:
　0.03% ~ 0.15%, Si: 1.8% ~ 7.0%, Mn:
　0.02% ~ 0.30%, S: 0.005% ~ 0.040%,
　acid-soluble
　Al: 0.010% ~
　0.065% N: 0.0030% ~ 0.0150% Cu: 0.03% ~
　0.60% Sn: 0% ~ 0.
　% 5, Ge, Se, Sb, Te, Pb or Bi, or any combination thereof: 0.0005% to 0.030% in total, and
　Fe and impurities: the balance
　has in a chemical composition represented,
　with an oxide film on the surface of the steel sheet,
　decarburizing the steel sheet for grain-oriented electrical steel sheet Cu / Fe emission intensity ratio at the interface region between the oxide film and the surface of the steel sheet is characterized in that it is 0.60 or less.
[0011]
　(3)
　heating the slab at a temperature range of 1300 ° C. ~ 1490 ° C.,
　obtaining a hot rolled steel sheet by performing hot rolling of the slab,
　the hot-rolled steel sheet wound in a temperature range of 600 ° C. or less a step,
　a step of performing a hot-rolled sheet annealing of the hot-rolled steel sheet,
　after the hot rolled sheet annealing, a step of obtaining a cold rolled steel sheet by performing cold rolling,
　the step of performing a decarburization annealing of the cold-rolled steel sheet If,
　after said decarburization annealing, an annealing separating agent containing MgO is coated, and performing finish annealing,
it has a
　step of performing the hot rolling, a rough rolling to the finishing temperature and 1200 ° C. or less and performing, the starting temperature and 1000 ° C. or higher, and a step of performing finish rolling in which the end temperature of 950 ° C. ~ 1100 ° C.,
　in the hot rolling, the finish within 300 seconds from the start of the rough rolling to start rolling,
　cooling within 10 seconds from the end of the finish rolling Speed starts cooling over 50 ° C. / sec,
　after the hot rolling, before the end of the cold rolling, nitrate, in pickling bath containing a pickling inhibitor, and a surfactant, the holding temperature 50 ° C. above and then, the holding time performs pickling to 30 seconds or more,
　the slab is a
　mass%,
　C: 0.03% ~ 0.15%, Si: 1.8% ~
　7.0%, Mn:
　% ~ 0.30 0.02%, S: 0.005% ~ 0.040%,
　acid-soluble
　Al: 0.010% ~ 0.065%, N: 0.0030% ~
　0.0150%, Cu:
　% 0.60 0.03%,
　Sn: 0% - 0.5%, Ge, Se, Sb, Te, Pb or Bi, or any combination thereof: 0.0005% to 0.030% in total, and
　the balance: Fe and impurities,
　the manufacturing method of the grain-oriented electrical steel sheet characterized by having a in chemical composition represented.
[0012]
　(4)
　the production method of the grain-oriented electrical steel sheet according to the pickling bath, characterized by further comprising a nitrate (3).
[0013]
　(5)
　heating the slab at a temperature range of 1300 ° C. ~ 1490 ° C.,
　obtaining a hot rolled steel sheet by performing hot rolling of the slab,
　the hot-rolled steel sheet wound in a temperature range of 600 ° C. or less a step,
　a step of performing a hot-rolled sheet annealing of the hot-rolled steel sheet,
　after the hot rolled sheet annealing, a step of obtaining a cold rolled steel sheet by performing cold rolling,
　the step of performing a decarburization annealing of the cold-rolled steel sheet If,
have,
　step of performing rolling the heat finishing rolling and performing rough rolling to the finishing temperature and 1200 ° C. or less, the starting temperature of 1000 ° C. or higher, and the termination temperature of 950 ° C. ~ 1100 ° C. and a step of performing,
　in the hot rolling, the rough rolling of the finish rolling is started within 300 seconds from the start,
　the cooling rate from the end of the finish rolling within 10 seconds is more than 50 ° C. / sec start cooling,
　after the hot rolling, before the end of the cold rolling , Nitric acid, in a pickling bath containing a pickling inhibitor, and a surfactant, a holding temperature of 50 ° C. or higher, subjected to pickling to a retention time of 30 seconds or more,
　the slab is a mass%,
　C: 0
　%
　~ 0.15 .03%, Si: 1.8% ~
　7.0%, Mn: 0.02% ~ 0.30%, S: 0.005% ~ 0.040%,
　acid-soluble Al: 0
　%
　~ 0.065 .010%, N: 0.0030% ~
　0.0150%, Cu: 0.03% ~ 0.60%,
　Sn: 0% ~ 0.5%, Ge, Se, Sb, Te , Pb or Bi, or any combination thereof: 0.0005% to 0.030% in total, and
　balance: Fe and impurities,
　leaving for grain-oriented electrical steel sheet characterized by having a in chemical composition represented manufacturing method of charcoal steel plate.
[0014]
　(6)
　the production method of decarburizing the steel sheet for grain-oriented electrical steel sheet according to the pickling bath, characterized by further comprising a nitrate (5).
Effect of the invention
[0015]
　According to the present invention, since the Cu concentration in the interface region between the primary coating and the steel sheet is appropriate, it is possible to obtain the adhesion and good magnetic properties with excellent primary coating and the steel sheet.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016]
[1] Figure 1 is an image obtained by photographing the surface of the sample after bending test.
FIG. 2 is a diagram showing the relationship between the Cu concentration at the interface region between the minimum bend radius peeling occurs between the primary coating and the steel sheet.
FIG. 3 is a diagram showing an example of measurement of Fe emission intensity, Cu emission intensity and Cu / Fe emission intensity ratio by GDS analysis.
DESCRIPTION OF THE INVENTION
[0017]
　It will be described in detail embodiments of the present invention.
[0018]
　For the purpose of improving the magnetic properties, making the grain oriented electrical steel sheet with a silicon steel material specific elements of Bi or the like is contained, the adhesion between the primary coating and the steel sheet is degraded. Conventionally, when formulating a scrap as a raw material for steel making, although Cu can be contained in the slab was known, Cu is an element for improving the magnetic properties, in particular problems with respect to adhesion of the primary coating since not an element of the contamination of the Cu from the scrap has not been a particular problem if it is a small amount. However, the present inventors discovered that when using a silicon steel material specific element described above is contained, the adhesiveness of the primary coating also to the extent that the Cu content is not the conventional problem has deteriorated, and Cu is thickened portion present on the surface of the steel sheet after decarburization annealing was found that this portion is causing degradation. Then, the present inventors have result of repeated further study, part Cu on the surface of the steel sheet was concentrated can not be removed by pickling by conventional processing conditions, in the manufacturing process, at a given condition Cu from the surface of the steel sheet by pickling has been found to be able to improve the adhesion of the primary coating by removing a portion was concentrated. The following describes these findings were obtained experimentally.
[0019]
　In a vacuum melting furnace, to produce a silicon steel material having a chemical composition shown in Table 1, obtained after heating the slab, plate thickness by performing a hot rolling the hot-rolled steel sheet of 2.3mm at 1350 ° C., then performed hot rolled sheet annealing, after pickling, the sheet thickness by performing cold rolling to obtain a cold-rolled steel sheet of 0.22 mm. Note that the silicon steel material shown in Table 1, the balance being Fe and impurities. Then, the cold-rolled steel sheet, subjected to primary recrystallization annealing including decarburization annealing, was coated with an annealing separator mainly comprised of MgO, perform final annealing to obtain a variety of grain-oriented electrical steel sheet. The resulting steel sheet coated with an insulating film, and baked. The obtained steel sheets, the magnetic flux density B 8 (intensity of the magnetic field flux density at 800A / m) was measured. Further, each of the samples were taken from the central portion of 50mm distant portion and coil width direction from an end of the coil width direction at the finish annealing was carried out wound put bending test in a cylindrical body 20 mm.phi. It was evaluated the adhesiveness of the primary coating from these results. Figure 1 shows an image obtained by photographing the surface of the sample after bending test in the manufacture steel plates with steel type MD1 ~ grades MD6. Further, the magnetic flux density B 8 shown in Table 2 the measurement results of. Note that the specific elements in Table 1, Ge, Se, Sb, Te, refers to Pb and Bi, in the column of a specific element "-" steels described and were not using a specific element.
[0020]
[Table 1]

[0021]
[Table 2]

[0022]
　From Table 2, the steel type MD4 and steel type MD6 ~ grades MD10 containing a predetermined amount of Cu with a particular element, or a high magnetic flux density B 1.94T 8 was obtained. In steel type MD1 and steel type MD3 containing no specific element, following a low magnetic flux density B 1.90T 8 it was obtained. Thus, by combining the specific elements and Cu, oriented electrical steel sheet having a high magnetic flux density was obtained.
[0023]
　As shown in FIG. 1, steels MD4 containing specific elements and Cu, the steels MD6 ~ grades MD10, and the Cu content is relatively high grades MD5, bending primary film after processing ends up exposed steel by peeling , adhesion becomes defective. In steels MD3 not containing steels MD1, Cu content is less steel type MD2 and special elements Cu content does not contain less special element, after bending without peeling the primary film, adhesion was good. Thus, when producing a grain-oriented electrical steel sheet with a slab containing specific elements and Cu, but oriented electrical steel sheet having a high magnetic flux density can be obtained, the adhesion is deteriorated.
[0024]
　Next, we examined the cause adhesion is deteriorated. In the production of steel sheet containing Cu, Cu along with the generation of oxide scale during slab heating before hot rolling is known to be concentrated in the surface layer of the slab. Cu is concentrated partially (Cu enriched portion) is being stretched by hot rolling, also in pickling after hot rolling, there is no hydrochloric acid or aqueous sulfuric acid is used for general pickling bath is dissolved . Therefore, Cu enriched portion remaining on the surface of the steel sheet after cold rolling, it was thought to degrade the adhesion between the primary coating and the steel sheet. To confirm this idea, the steels MD4 place, the hot-rolled steel sheet after hot rolling to produce a grain-oriented electrical steel sheet by pickling under various conditions were subjected to the same bending test, specific conditions adhesion between the primary coating and the steel sheet when performing pickling is improved in.
[0025]
　Accordingly, the present inventors have investigated the effect of Cu concentration at the interface region between the primary coating and steel sheet on the adhesion of the primary coating. In steel type MD3 and steel type MD4, by changing pickling conditions after hot rolling to a variety, to produce a grain-oriented electrical steel sheet having different degree of removing the Cu enriched portion in the surface of the steel sheet, the primary coating and the steel sheet the Cu concentration in the interface region between were measured by GDS analysis (glow discharge optical emission spectrometry). Also, the bending radius is changed to 10 mm ~ 30 mm, was investigated the relationship between the minimum bend radius stripping and Cu concentration occurs at the interface region between the primary coating and the steel sheet. Peeling and the area ratio of the peeled portion was 10% or more. Incidentally, Cu concentration ratio of the emission intensity of the emission intensity and Fe in Cu in GDS analysis, i.e., it was decided to substitute Cu / Fe emission intensity ratio. Cu concentration, there is a correlation with Cu / Fe emission intensity ratio. The results are shown in Figure 2. As shown in FIG. 2, the steels MD3 not containing Te, a both good adhesion, there was no correlation between the adhesion and the Cu concentration at the interface region between the primary coating and the steel sheet. On the other hand, the steels MD4 was contained Te, adhesiveness was good when the Cu concentration at the interface region between the primary coating and the steel plate is low (when Cu / Fe emission intensity ratio of 0.30 or less).
[0026]
　And Cu in the steel, if the specific elements of Te, etc. coexist, internal oxidation SiO generated by decarburization annealing 2 when reacted with MgO in the annealing separator, during the oxidation film is finish annealing comprising, on the surface of the steel sheet specific elements and Cu such as a thickened Te together, segregates at the interface between the steel sheet and the oxide film to form a liquid phase film. And deterioration of adhesiveness of the primary coating, this by a liquid phase film internal oxidation SiO 2 reaction between the oxide film and the MgO containing suppressed, is presumed to be due to planarize the structure of the interface between the primary coating and the steel sheet that.
[0027]
　Therefore, when manufacturing grain-oriented electrical steel sheet with a silicon steel material containing specific elements and Cu, as a steel sheet prior to the application of the annealing separator, the use of the steel sheet with reduced Cu concentration on the surface of the steel sheet, can Cu concentration at the interface region between the primary coating and the steel sheet to produce a low-oriented electrical steel sheet, adhesion of the high magnetic flux density and excellent primary film can be obtained.
[0028]
　The present invention has been made a result of studies described above. The following describes decarburizing steel sheets for grain-oriented electrical steel sheet and grain-oriented electrical steel sheet according to the embodiment of the present invention.
[0029]
　The chemical composition of the slab is described for use in decarburization sheet and its production for grain-oriented electrical steel sheet according to the embodiment of the present invention. Although details will be described later, decarburization steel for grain-oriented electrical steel sheet according to the embodiment of the present invention, heating the slab, hot rolling, hot-rolled sheet annealing, manufactured through cold rolling, and the decarburization annealing, etc. that. Therefore, the chemical composition of the slab used in the decarburizing the steel sheet and manufacturing for grain-oriented electrical steel sheet not only characteristics of the decarburization steel sheet is taken into consideration these processes. In the following description, a unit of content of each element contained in the decarburized steel sheet or slab for grain oriented electrical steel sheet "%" it is especially meant to "mass%" unless otherwise specified. Decarburization steel for grain-oriented electrical steel sheet according to the present embodiment, C: 0.03% ~ 0.15%, Si: 1.8% ~ 7.0%, Mn: 0.02% ~ 0.30 %, S: 0.005% ~ 0.040%, acid-soluble Al: 0.010% ~ 0.065%, N: 0.0030% ~ 0.0150%, Cu: 0.03% ~ 0.60 Table of Fe and impurities:%, Sn: 0% ~ 0.5%, Ge, Se, Sb, Te, Pb or Bi, or any combination thereof: 0.0005% to 0.030% in total, and the balance It has a chemical composition that is. As the impurity, those included in raw materials such as ores and scrap, intended to be included in the manufacturing process, is exemplified.
[0030]
　(C: 0.03% ~ 0.15%)
　C stabilizes secondary recrystallization. The C content is less than 0.03%, the crystal grains are abnormally grain growth at the time of the heating of the slab, the secondary recrystallization in the finish annealing in the production of grain-oriented electrical steel sheet becomes insufficient. Therefore, C content is 0.03% or more. The C content of 0.15 percent, not only the time of decarburization annealing after cold rolling becomes long, because the decarburization tends to become insufficient, causing magnetic aging in the product. Therefore, C content is at most 0.15%.
[0031]
　(Si: 1.8% ~
　7.0%) Si reduces the eddy current loss by increasing electrical resistance of the steel. Si content is less than 1.8%, can not be suppressed eddy current loss of the product. Therefore, Si content is 1.8% or more. The Si content of 7.0 percent, the workability is remarkably deteriorated, it is difficult to cold rolling at room temperature. Therefore, Si content is at most 7.0%.
[0032]
　(Mn: 0.02% ~
　0.30%) Mn forms MnS, which acts as an inhibitor. The Mn content is less than 0.02%, MnS is insufficient required to cause secondary recrystallization. Therefore, Mn content is 0.02% or more. The Mn content of 0.30 percent, well dissolved in MnS during heating of the slab becomes difficult, size of MnS to reprecipitation easily coarsened during hot rolling. Therefore, Mn content is at most 0.30%.
[0033]
　(S: 0.005% ~ 0.040%)
　S is formed and Mn, the MnS that acts as an inhibitor. The S content is less than 0.005%, a sufficient inhibitor effect can not be obtained to express the secondary recrystallization. Thus, S content is 0.005% or more. The S content 0.040%, the edge cracking is likely to occur during hot rolling. Thus, S content is 0.040% or less.
[0034]
　(Acid-soluble Al: 0.010% ~
　0.065%) Al forms an AlN that functions as inhibitor. The Al content is less than 0.010%, because the inhibitor strength is low AlN is insufficient, the effect is not exhibited. Therefore, Al content is 0.010% or more. The Al content 0.065 percent, AlN reduces the inhibitor strength coarsened. Therefore, Al content is set to 0.065% or less.
[0035]
　(N: 0.0030% ~ 0.0150%)
　N forms a Al, an AlN that functions as inhibitor. N content is less than 0.0030% or not sufficient inhibitor effect. Therefore, N content is 0.0030% or more. N content is 0.0150% greater, surface defects called blisters occur. Therefore, N content is at most 0.0150%.
[0036]
　(Cu: 0.03% ~
　0.60%) Cu enhances the specific resistance of the steel sheet remaining on the steel sheet, and reducing the core loss. Further, Cu strengthens the inhibitor required for secondary recrystallization, increasing the magnetic flux density oriented electrical steel sheet. The Cu content is less than 0.03%, its effect can not be obtained sufficiently, can not stably produce grain-oriented electrical steel sheet having a high magnetic flux density. Therefore, Cu content is 0.03% or more. The Cu content of 0.60 percent, its effect can be saturated. Therefore, Cu content is 0.60%.
[0037]
　(Ge, Se, Sb, Te, Pb or Bi, or any combination thereof:
　0.0005% to 0.030% in total) to strengthen Ge, Se, Sb, Te, Pb and Bi are inhibitors, magnetic flux density the improved magnetic flux density B 8 contributes to stable production of grain-oriented electrical steel sheet has a higher magnetic flux density 1.94T. Ge, Se, Sb, Te, is less than 0.0005% by Pb or Bi, or any combination thereof total, the effect is small. Therefore, Ge, Se, Sb, Te, Pb or Bi, or any combination thereof, be the total 0.0005% or more. Ge, Se, Sb, Te, 0.030 percent by Pb or Bi, or any combination of these total, not only the effect is saturated, the film adhesion is remarkably deteriorated. Therefore, Ge, Se, Sb, Te, Pb or Bi, or any combination thereof, and 0.030% or less in total. Ge, Se, Sb, Te, both the Pb and Bi small solid solubility in iron, tend to collect at the interface between the interface and the precipitate and the steel sheet between the primary coating and the steel sheet. While such properties are effective for strengthening the inhibitors, the formation of the primary film because of the adverse effect tendency is presumed to degrade the coating adhesion.
[0038]
　Sn is not an essential element, a good optional elements be contained appropriately limit the predetermined amount decarburization steel for grain-oriented electrical steel sheet.
[0039]
　(Sn: 0% ~
　0.5%) Sn stabilizes secondary recrystallization, to reduce the particle size of the secondary recrystallization. Therefore, Sn may be contained. In order to obtain the advantageous effects sufficiently, Sn content is preferably 0.05% or more. The Sn content of 0.5 percent, its effect can be saturated. Accordingly, Sn content is 0.5% or less. For a higher yield of product and further reduce the occurrence of cracks during cold rolling, Sn content is preferably 0.2% or less.
[0040]
　Decarburization steel for grain-oriented electrical steel sheet according to the embodiment of the present invention comprises an oxide film on the surface of the steel sheet, with Cu / Fe emission intensity ratio at the interface region between the surface of the oxide film and the steel sheet is 0.60 or less is there. An oxide film formed by the decarburization annealing, the Cu / Fe emission intensity ratio at the interface region between the surface of the steel sheet by 0.60 or less, Cu in the interface region between the primary coating and the steel sheet is subsequently formed so as not increased the concentration. To obtain adhesion between the higher primary film and steel sheet, Cu / Fe emission intensity ratio at the interface region between the surface of the oxide film and the steel sheet is preferably 0.40 or less.
[0041]
　Cu concentration in the interface region between oxide film and the steel sheet in the decarburization steel sheet, and be replaced by Cu / Fe emission intensity ratio obtained using GDS analysis. Cu concentration, there is a correlation with Cu / Fe emission intensity ratio. The interface region is intended to refer to areas such as the following. Measurement of the elemental distribution in the depth direction by GDS analysis, toward the inside from the surface of the decarburized steel sheet, while the peak intensity of the main elements O and Si to form the oxide film is reduced, the peak intensity of Fe increases to. The interface region has a depth from the surface of the decarburized steel sheet peak intensity of Fe corresponds to the sputtering time becomes maximum, from the surface of the decarburized steel sheet peak intensity of Fe corresponds to sputtering time as a half thereof It refers to a region between the depth. In GDS analysis, detection wavelength when measuring the emission intensity, the emission intensity of Fe Cu, respectively 327.396Nm, and 271.903Nm. Fe emission intensity obtained by using a GDS analysis, shows an example of measurement of Cu emission intensity and Cu / Fe emission intensity ratio in FIG. Area A in FIG. 3 is a surface area that is specified above. The Cu / Fe emission intensity ratio, and be evaluated by the "average at each measurement point in the interface region (Cu emission intensity / Fe emission intensity)" in the interface region identified as described above.
[0042]
　Next, a description will be given chemical composition of the grain-oriented electrical steel sheet according to the embodiment of the present invention. Although details will be described later, oriented electrical steel sheet according to the embodiment of the present invention, heating the slab, hot rolling, hot-rolled sheet annealing, cold rolling, is produced through application of annealing separator, and finishing annealing, etc. that. It may include a purification annealing to finish annealing. Therefore, the chemical composition of the grain-oriented electrical steel sheet, not only the properties of the grain-oriented electrical steel sheet, is taken into consideration these processes. In the following description, a unit of content of each element contained in the grain-oriented electrical steel sheet "%" is especially meant to "mass%" unless otherwise specified. Oriented electrical steel sheet according to the present embodiment, Si: 1.8% ~ 7.0%, Cu: 0.03% ~ 0.60%, and balance: having a chemical composition represented by Fe and impurities ing. As the impurity, those included in raw materials such as ores and scrap, intended to be included in the manufacturing process, specifically, Mn, Al, C, N, and S, and the like. Also, sometimes elements such as B derived from the annealing separator remains as an impurity.
[0043]
　(Si: 1.8% ~
　7.0%) Si reduces the eddy current loss by increasing electrical resistance of the steel. The Si content is less than 1.8%, it can not be obtained the effects thereof. Therefore, Si content is 1.8% or more. The Si content of 7.0 percent, the workability is remarkably deteriorated. Therefore, Si content is at most 7.0%.
[0044]
　(Cu: 0.03% ~
　0.60%) Cu enhances the effect of the inhibitor in the production of grain-oriented electrical steel sheet, highly are integrated by {110} <001> orientation of the orientation of the crystal grains in the product, further enhanced the effect by being contained together with the specific element. Further, Cu can be finally residue, and reducing the core loss by increasing specific resistance. The Cu content is less than 0.03%, its effect can not be obtained sufficiently. Therefore, Cu content is 0.03% or more. The Cu content of 0.60 percent, its effect can be saturated. Therefore, Cu content is 0.60%. Incidentally, Cu, when formulated with scrap as a raw material in the step of melting the steel may also be mixed therefrom.
[0045]
　The oriented electrical steel sheet according to the embodiment of the present invention, comprising a primary film containing forsterite on the surface of the steel sheet, with Cu / Fe emission intensity ratio at the interface region between the primary coating and the surface of the steel sheet is 0.30 or less is there. Of the components constituting the primary film, forsterite as the main component is contained more than 70 wt%. The Cu / Fe emission intensity ratio by 0.30 or less, it is possible to obtain an excellent grain-oriented electrical steel sheet adhesion to the primary coating and the steel sheet. To obtain adhesion between the higher primary film and steel sheet, Cu / Fe emission intensity ratio at the interface region between the primary coating and the steel sheet surface is preferably 0.20 or less.
[0046]
　Cu concentration at the interface region between the primary coating and the steel sheet in the oriented electrical steel sheet, and be replaced by Cu / Fe emission intensity ratio obtained using GDS analysis. Cu concentration, there is a correlation with Cu / Fe emission intensity ratio. The interface region is intended to refer to areas such as the following. Measurement of the elemental distribution in the depth direction by GDS analysis, toward the inside from the surface of the grain-oriented electrical steel sheet, while O is the main element forming a primary film, the peak intensity of Mg and Si decreases, the peak of Fe intensity increases. The interface region has a depth from the surface of the grain-oriented electrical steel sheet peak intensity of Fe corresponds to the sputtering time becomes the maximum peak intensity of Fe grain-oriented electrical steel sheet that corresponds to the sputtering time as a half thereof It refers to a region between the depth from the surface. The depth from the surface of the grain-oriented electrical steel sheet that corresponds to the sputtering time to peak intensity of Fe becomes maximum is the peak intensity of Mg corresponds substantially to is not made depth detection. In GDS analysis, detection wavelength when measuring the emission intensity, the emission intensity of Fe Cu, respectively 327.396Nm, and 271.903Nm.
[0047]
　Next, a method for manufacturing the decarburization steel for grain-oriented electrical steel sheet according to the embodiment of the present invention. In the manufacturing method of decarburizing the steel sheet for grain-oriented electrical steel sheet according to the present embodiment performs heating of the slab, hot rolling, hot-rolled sheet annealing, cold rolling, decarburization annealing, and pickling or the like.
[0048]
　First, after a slab of molten steel to be used for the production of the above decarburization steel in a conventional manner, heat and hot rolling of the slab.
[0049]
　Is less than the slab heating temperature is 1300 ° C., it can not dissolve the precipitates such as MnS, large variations in the magnetic flux density of the product. Accordingly, the slab heating temperature, and 1300 ° C. or higher. Slab heating temperature in the 1490 ° C. greater than the slab is melted. Accordingly, the slab heating temperature, and 1490 ° C. or less.
[0050]
　In hot rolling, it carried out rough rolling to the finishing temperature and 1200 ° C. or less, the start temperature of 1000 ° C. or more, performing finish rolling termination temperature was set to 950 ℃ ~ 1100 ℃. The end temperature is 1200 ° C. than the rough rolling, MnS or MnSe precipitation in the rough rolling is not promoted, Cu in the finishing rolling 2 S ends up generating, magnetic properties of the product are deteriorated. Therefore, the end temperature of the rough rolling is set to 1200 ° C. or less. Is less than the finish rolling start temperature is 1000 ° C., below the 950 ° C. Exit temperature of the finish rolling, Cu 2 S is easily precipitated, the magnetic properties of the product is not stable. Therefore, the starting temperature of finish rolling is set to 1000 ° C. or higher. The end temperature is lower than 950 ° C. of finish rolling, Cu 2 S is easily precipitated, the magnetic characteristics are not stable. Further, when the temperature difference between the slab heating temperature is too large, it is difficult to adjust the temperature history of hot-rolled coils entire length, it is difficult to build in homogeneous inhibitor over the entire length of the hot-rolled coil. Therefore, the end temperature of finish rolling is set to 950 ° C. or higher. The end temperature is 1100 ° C. than the finish rolling can not be controlled to be dispersed MnS and MnSe fine. Therefore, the end temperature of finish rolling is set to 1100 ° C. or less.
[0051]
　From the start of the rough rolling finishing within 300 seconds to start rolling. The time is 300 seconds more than the start of rough rolling to the start of the finish rolling, 50 nm or less of MnS or MnSe which acts as an inhibitor is not dispersed, the secondary recrystallization grain diameter control and finish annealing the decarburization annealing becomes difficult, magnetic characteristics are deteriorated. Therefore, the time from the start of rough rolling to the start of the finish rolling is within 300 seconds. The lower limit of the time is not particularly necessary to set if normal rolling. In less than 30 seconds until the start of the finish rolling from the start of rough rolling, the precipitation amount of MnS or MnSe is not sufficient, the secondary recrystallized grains may become difficult to develop during finish annealing.
[0052]
　From the end of finish rolling within 10 seconds, the cooling rate starts to cool over 50 ° C. / sec. The time is more than 10 seconds from the end of finish rolling until the start of cooling, Cu 2 S is easily precipitated, the magnetic properties of the product is not stable. Therefore, the time from the end of finish rolling until the start of cooling to a maximum of 10 seconds, preferably within 2 seconds. If it is less than finish rolling after the cooling rate is 50 ° C. / sec, Cu 2 S is easily precipitated, the magnetic properties of the product is not stable. Therefore, the cooling rate after the finish rolling is set to 50 ° C. / sec or higher.
[0053]
　Then, they wound up in a temperature range of 600 ℃ or less. The coiling temperature is 600 ° C. greater, Cu 2 S is easily precipitated, the magnetic properties of the product is not stable. Therefore, the coiling temperature is set to 600 ° C. or less.
[0054]
　Next, the hot-rolled sheet annealing the resulting hot-rolled steel sheet. When the termination temperature of finish rolling was Tf, the holding temperature of the hot-rolled sheet annealing 950 ℃ ~ (Tf + 100) to ° C.. Holding temperature is less than 950 ° C., can not be homogeneous inhibitor over the entire length of the hot-rolled coils, the magnetic properties of the product is not stable. Therefore, the holding temperature is set to 950 ° C. or higher. The holding temperature is (Tf + 100) ℃ greater, MnS which is finely precipitated in the hot rolling rapidly growing, secondary recrystallization becomes unstable. Therefore, the holding temperature is set to (Tf + 100) ℃ or less.
[0055]
　Next, obtain a cold-rolled steel sheet performed twice or more cold rolling sandwiching the rolling or intermediate annealing between single cold. After that, the decarburization annealing of cold-rolled steel sheet. By performing the decarburization annealing, SiO on the surface of the steel plate 2 oxide film containing it is formed. Cold rolling and decarburization annealing can be carried out by a general method.
[0056]
　After hot rolling, before the end of the cold rolling, for example, between the hot rolling and hot rolled sheet annealing, or between the hot-rolled sheet annealing and cold rolling, nitrate, pickling inhibitors and surfactants in pickling bath containing an active agent, a holding temperature of 50 ° C. or more, the retention time performing pickling to 30 seconds or more. By performing such pickling, it is possible to remove the Cu enriched portion of the surface of the steel sheet. By removing the Cu enriched portion, the Cu concentration on the surface of the decarburized steel sheet after decarburization annealing, the Cu / Fe emission intensity ratio obtained by GDS analysis can be 0.60 or less. The content of nitric acid is less than 5 g / l, it can not be sufficiently removed Cu enriched portion. Accordingly, the content of nitric acid and 5 g / l or more. In the 200 g / l greater than the content of nitric acid, the cost is increased effects thereof are saturated. Accordingly, the content of nitric acid is less 200 g / l. In less than 0.5 g / l content of pickling inhibitors, excessive dissolution of the surface of the steel sheet occur locally, and vigorously rough surface with unevenness. Accordingly, the content of the pickling inhibitors and 0.5 g / l or more. When the content of the pickling inhibitor 10 g / l greater than the cost rises effects thereof are saturated. Accordingly, the content of the pickling inhibitor or less 10 g / l. The content of the surfactant is less than 0.5 g / l, it can not be sufficiently removed Cu enriched portion. Accordingly, the content of the surfactant and 0.5 g / l or more. The content of the surfactant is 10 g / l greater than the cost rises effects thereof are saturated. Accordingly, the content of the surfactant is less 10 g / l. The holding temperature is lower than 50 ° C., the rate of removing scale by pickling is significantly lowered, productivity is lowered. Therefore, the holding temperature is set to 50 ° C. or higher. The retention time is less than 30 seconds, can not be sufficiently remove scale. Therefore, the holding time is 30 seconds or more.
[0057]
　The pickling inhibitor, preferably can be an organic-based inhibitors, for example, amine derivatives, Merukaputon acids can be used sulfides, thiourea and derivatives thereof. The surfactant can be preferably used ethylene glycol, glycerin and the like.
[0058]
　The pickling bath, a nitrate, may include, for example, sodium nitrate. By performing the pickling in the pickling bath containing the nitrate, it can be more reliably removed Cu enriched portion in the surface of the steel plate, the Cu concentration on the surface of the decarburized steel sheet after decarburization annealing, the GDS analysis the Cu / Fe emission intensity ratio obtained Te can be set to 0.40 or less. Content is less than 0.5 g / l of nitrate, it may not be possible to reliably remove the Cu enriched portion. Accordingly, the content of nitrate and 0.5 g / l or more. The content of nitrate 10 g / l greater than the cost rises effects thereof are saturated. Accordingly, the content of nitrate is less 10 g / l.
[0059]
　In this way, it is possible to produce a decarburized steel sheet for grain-oriented electrical steel sheet according to the present embodiment.
[0060]
　Next, a method for manufacturing a grain-oriented electrical steel sheet according to the embodiment of the present invention. In the method of manufacturing the oriented electrical steel sheet according to the present embodiment performs heating of the slab, hot rolling, hot-rolled sheet annealing, cold rolling, decarburization annealing, coating of an annealing separating agent, finish annealing, and pickling or the like . Heating the slab, hot rolling, hot-rolled sheet annealing, cold rolling, the decarburization annealing and pickling can be performed similarly to the manufacturing method of decarburizing the steel sheet for the grain-oriented electrical steel sheet.
[0061]
　The annealing separating agent containing MgO is applied to the decarburized steel sheet obtained, perform finish annealing. For pickling, after hot rolling, it shall be made before the end of the cold rolling. Annealing separator contains MgO, the proportion of MgO in the annealing separator agent is, for example, 90 mass% or more. In the finish annealing, after the completion of secondary recrystallization, it may be subjected to purification annealing. Coating and finishing annealing of annealing separator can be carried out by a general method.
[0062]
　Performing pickling, by controlling the Cu concentration on the surface of the steel sheet, and primary film composed mainly of forsterite formed on the surface of the steel sheet after finish annealing thereafter performed, the Cu concentration in the interface region between the steel sheet obtained by GDS analysis Cu / Fe emission intensity ratio is 0.30 or less. Further, by performing the pickling in the pickling bath containing the nitrate, it can be more reliably removed Cu enriched portion in the surface of the steel plate, a primary coating formed on the surface of the steel sheet after finish annealing, and the steel sheet for Cu concentration at the interface region, the Cu / Fe emission intensity ratio obtained by GDS analysis can be 0.20 or less.
[0063]
　In this way, it is possible to manufacture a grain-oriented electrical steel sheet according to the present embodiment. After finish annealing, it may form an insulating film by coating and baking.
[0064]
　From the above, according to the manufacturing method of preparation and oriented electrical steel sheet decarburization steel for grain-oriented electrical steel sheet according to the embodiment of the present invention, it is possible to appropriately control the Cu concentration at the surface of the steel sheet may magnetic properties obtained decarburization steel for better oriented electrical steel sheet and a grain oriented electrical steel sheet adhesion to a good primary coating and the steel sheet.
[0065]
　Having described in detail preferred embodiments of the present invention, the present invention is not limited to such an example. It would be appreciated by those skilled in the relevant field of technology of the present invention, within the scope of the technical idea described in the claims, it is intended to cover various changes and modifications , also such modifications are intended to fall within the technical scope of the present invention.
Example
[0066]
　Next, the decarburizing the steel sheet and grain-oriented electrical steel sheet for grain-oriented electrical steel sheet according to the embodiment of the present invention will be specifically described below showing Examples. Examples shown below are only just examples of decarburizing the steel sheet and grain-oriented electrical steel sheet for grain-oriented electrical steel sheet according to the embodiment of the present invention, decarburization steel and direction for grain-oriented electrical steel sheet according to the present invention sex electromagnetic steel sheet is not limited to the following examples.
[0067]
　In a vacuum melting furnace, to produce a silicon steel material having a chemical composition of steels MD4-steel type MD10 shown in Table 1, after heating the slab at a temperature shown in Table 3 to Table 5, under the conditions shown in Table 3 to Table 5 thickness performing hot rolling to obtain a hot-rolled steel sheets of 2.3 mm, it was wound up at a temperature shown in Table 3 to Table 5. Then, after annealing the hot-rolled steel sheet was subjected to pickling using a pickling bath B1 ~ San'araiyoku B3 shown in Table 6. Using sodium nitrate as the nitrate contained in San'araiyoku B2. Thereafter, the plate thickness by performing cold rolling under the conditions shown in Table 3 to Table 5 to obtain a cold-rolled steel sheet of 0.22 mm. Next, the obtained cold-rolled steel sheet, after obtaining the decarburization steel sheet by performing a primary recrystallization annealing including decarburization annealing, finish and coated with an annealing separator composed of MgO as a main component in the decarburization steel perform annealing, resulting finished annealed sheets in the insulating film was coated baked to obtain a grain-oriented electrical steel sheet.
[0068]
　From each of the obtained decarburized steel sheet and grain-oriented electrical steel sheet samples were harvested perform GDS analysis, the emission intensity of the emission intensity and Fe in Cu in the interface region between oxide film and the steel sheet was measured for decarburization steel, the oriented electrical steel sheet to measure the emission intensity of the emission intensity and Fe in Cu in the interface region between the primary coating and the steel sheet consisting mainly of forsterite was determined Cu / Fe emission intensity ratio, respectively. The resulting samples were taken from the directional electromagnetic steel magnetic flux density B 8 were measured. Each sample was taken from the central portion of 50mm distant portion and coil width direction from an end of the coil width direction at the finish annealing was carried out wound put bending test in a cylindrical body 20 mm.phi. The length of the portion is deformed over a curved surface of the cylinder by bending is about 30 mm, were evaluated coating adhesion by coating remaining ratio at the deformed portion. For evaluation of the coating adhesion, when the film residual ratio was 70% or more it was judged as excellent in coating adhesion. The results are shown in Tables 3 to 5. Incidentally, underlined in Table 3 to Table 5 indicates that the number is out of range of the present invention. Underlined in Table 6 indicates that the condition is outside the scope of the present invention.

claims.1 　By
　mass%,
　Si: 1.8% ~ 7.0%, Cu: 0.03% ~ 0.60%, and
　balance: Fe and impurities,
　have in a chemical composition represented,
　fault on the surface of the steel sheet comprising a primary film containing stellite,
　oriented electrical steel sheet, wherein the Cu / Fe emission intensity ratio at the interface region between the primary coating and the surface of the steel sheet is 0.30 or less.
[Requested item 2]
　By
　mass%,
　C:
　0.03% ~ 0.15%, Si: 1.8% ~ 7.0%,
　Mn: 0.02% ~ 0.30%, S: 0.005% ~ 0.040 %,
　acid-soluble
　Al: 0.010% ~
　0.065%, N: 0.0030% ~ 0.0150%, Cu:
　0.03% ~ 0.60%, Sn: 0% ~ 0.5%,
　Ge, Se, Sb, Te, Pb or Bi, or any combination thereof: 0.0005% to 0.030% in total, and
　balance: Fe and impurities,
　have in a chemical composition represented,
　the surface of the steel sheet with an oxide film,
　decarburization steel for a grain oriented electrical steel sheet Cu / Fe emission intensity ratio at the interface region between the oxide film and the surface of the steel sheet is characterized in that it is 0.60 or less.
[Requested item 3]
　Heating the slab in a temperature range of 1300 ° C. ~ 1490 ° C.,
　obtaining a hot rolled steel sheet by performing hot rolling of the slab,
　a step of winding the hot-rolled steel sheet in a temperature range of 600 ° C. or less,
　and performing hot-rolled sheet annealing of the hot-rolled steel sheet,
　after the hot rolled sheet annealing, a step of obtaining a cold rolled steel sheet by performing cold rolling,
　and performing decarburization annealing of the cold-rolled steel sheet,
　said after decarburization annealing, an annealing separating agent containing MgO is coated, and performing finish annealing,
has a
　step of performing the hot rolling, and performing rough rolling to the finishing temperature and 1200 ° C. or less the starting temperature of 1000 ° C. or higher, and a step of performing finish rolling in which the end temperature of 950 ° C. ~ 1100 ° C.,
　in the hot rolling, starting the finish rolling within 300 seconds from the start of the rough rolling and,
　the cooling rate from the end of the finish rolling to within 10 seconds Start the 0 ° C. / sec or more cooling,
　after the hot rolling, before the end of the cold rolling, nitrate, in pickling bath containing a pickling inhibitor, and a surfactant, a holding temperature of 50 ° C. or higher , retention time performs pickling to 30 seconds or more,
　the slab is a
　mass%,
　C: 0.03% ~ 0.15%, Si: 1.8% ~
　7.0%, Mn: 0.
　% ~ 0.30 02%, S: 0.005% ~ 0.040%,
　acid-soluble
　Al: 0.010% ~ 0.065%, N: 0.0030% ~
　0.0150%, Cu: 0.
　% 0.60 03%,
　Sn: 0% - 0.5%, Ge, Se, Sb, Te, Pb or Bi, or any combination thereof: 0.0005% to 0.030% in total, and
　the balance : Fe and impurities,
　the manufacturing method of the grain-oriented electrical steel sheet characterized by having a chemical composition expressed in.
[Requested item 4]
　Method for producing a grain-oriented electrical steel sheet according to claim 3, wherein the pickling bath, characterized in that it further comprises a nitrate.
[Requested item 5]
　Heating the slab in a temperature range of 1300 ° C. ~ 1490 ° C.,
　obtaining a hot rolled steel sheet by performing hot rolling of the slab,
　a step of winding the hot-rolled steel sheet in a temperature range of 600 ° C. or less,
　and performing hot-rolled sheet annealing of the hot-rolled steel sheet,
　after the hot rolled sheet annealing, a step of obtaining a cold rolled steel sheet by performing cold rolling,
　and performing decarburization annealing of the cold-rolled steel sheet,
the a,
　step of performing rolling the heat step of performing a step of performing rough rolling to the finishing temperature and 1200 ° C. or less, the start temperature of 1000 ° C. or more, the finish rolling termination temperature was set to 950 ° C. ~ 1100 ° C. has the door,
　in the hot rolling, the finish rolling begins, within 300 seconds from the start of the rough rolling
　start cooling the cooling rate is not less than 50 ° C. / sec within 10 seconds from the end of the finish rolling and,
　after the hot rolling, before the end of the cold rolling, nitrate In pickling bath containing a pickling inhibitor, and a surfactant, a holding temperature of 50 ° C. or higher, subjected to pickling to a retention time of 30 seconds or more,
　the slab is a mass%,
　C: 0.03%
　0.15%
　7.0%,~, Mn: 0.02% ~ 0.30%, S: 0.005% ~ 0.040%,
　acid-soluble Al: 0.010%
　0.065%
　0.0150%, Cu: 0.03% ~ 0.60%,
　Sn: 0% ~ 0.5%, Ge, Se, Sb, Te, Pb or of Bi, or any combination: 0.0005% to 0.030% in total, and
　balance: Fe and impurities,
　decarburization steel for grain-oriented electrical steel sheet characterized by having a in chemical composition represented Production method.
claim. 6]
　Manufacturing method of decarburizing the steel sheet for grain-oriented electrical steel sheet according to claim 5, wherein the pickling bath, characterized in that it further comprises a nitrate.