JPH10195536A - Manufacturing method of grain-oriented electrical steel sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably obtain a grain oriented silicon steel sheet excellent in glass coating characteristics and magnetic properties, at the time of producing a grain oriented silicon steel sheet from a silicon-contg. steel by a series of process, by regulating the content of Si and the content of O in a surface oxidizing layer of a process-annealed layer to prescribed ranges. SOLUTION: A silicon-contg. steel is subjected to hot rolling, is thereafter subjected to cold rolling for two times including process annealing, is subjected to final finishing, is next subjected to decarburizing annealing in wet hydrogen, is thereafter applied with separation agent for annealing and is subjected to finish annealing to produce a grain oriented silicon steel sheet. At this time, the content of Si and the content of O in a surface oxidizing layer of the process-annealed sheet are measured by glow discharge spectrometry, and at least one condition among the cooling atmosphere, grinding conditions and pickling conditions after the process annealing is controlled so as to regulate each integrated intensity ratio thereof is regulated to 0.7 to 1.2 and 0.95 to 1.12. In this way, the grain oriented silicon steel sheet stable in coating quality and magnetic properties can advantageously be obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a grain-oriented electrical steel sheet, and in particular, by controlling the amounts of Si and O in a surface oxide layer of an intermediate annealed sheet to an appropriate range.
It is intended to advantageously improve the magnetic properties and glass coating properties of a product plate.

[0002]

2. Description of the Related Art Grain-oriented electrical steel sheets are used as soft magnetic materials.
It is mainly used as an iron core material of a transformer or a rotating machine, and is required to have high magnetic flux density and small iron loss and magnetostriction as magnetic characteristics. Except in special cases, a forsterite (Mg ₂ SiO ₄ ) -based glass coating is generally formed on the surface of such a grain-oriented electrical steel sheet. This coating contributes not only to the electrical insulation of the surface but also to the improvement of iron loss and magnetostriction by imparting tensile strength to the steel sheet due to its low thermal expansion property.

[0003] The above-mentioned glass coating is formed by finish annealing. The formation behavior of the glass coating affects the behavior of MnS, MnSe, AlN, etc., which are inhibitor components in steel. It also affects the secondary recrystallization itself, which is an essential process for obtaining. Further, the formed glass film has a function of sucking up the unnecessary inhibitor component after the completion of the secondary recrystallization into the glass film and purifying the steel, which helps to reduce the hysteresis loss of the steel plate. Therefore, to form the glass coating uniformly is one of the important points that affect the product quality of the grain-oriented electrical steel sheet.

[0004] The formed glass coating must, of course, be uniform and defect-free and have excellent adhesion to withstand shearing, punching and bending. It must be smooth and have a high occupancy when laminated to an iron core.

[0005] In order to form a glass coating on the surface of a grain-oriented electrical steel sheet, after cold rolling to a desired final sheet thickness, decarburization /
Primary recrystallization annealing, that is, continuous annealing at a temperature of 700 to 900 ° C. in wet hydrogen makes the structure after cold rolling primary recrystallized and also reduces C, which causes magnetic after-effect, as much as possible. At the same time, a sub-scale mainly composed of silica is formed on the surface of the steel sheet by oxidation, and then an annealing separator mainly composed of MgO is applied onto the steel sheet, and then wound around a coil, and then reduced or non-oxidized. This is performed by performing high-temperature finish annealing at a temperature of about 1000 ° C. to 1200 ° C. in an atmosphere. Thus, a glassy insulating film called forsterite represented by the following formula is formed. 2MgO + SiO ₂ → Mg ₂ SiO ₄ This glass coating is a ceramic coating in which fine crystals of about 1 micron are densely integrated.

As described above, the forsteritic glass coating is formed by using an oxide called a subscale generated in the surface layer of a steel sheet in decarburization and primary recrystallization annealing as a raw material. The amount and distribution not only affect the nucleation and grain growth behavior of forsterite, but also affect the mechanical strength of the glass coating, and thus have a great effect on the coating quality after finish annealing.

[0007] The other material of the glass film
The annealing separator mainly composed of MgO is generally applied to a steel sheet as a slurry suspended in water. Therefore, even after drying, it retains H ₂ O physically adsorbed on the surface and partially hydrates to change to Mg (OH) ₂ . These H ₂ O
Is continuously released in small amounts up to around 800 ° C during finish annealing, so the steel sheet surface is oxidized. Such an oxidation phenomenon is called additional oxidation, which affects the formation behavior of forsterite and leads to oxidation / decomposition of the inhibitor. The susceptibility to this oxidation depends on the quality (physical properties) of the subscale produced by decarburization and primary recrystallization annealing.

Several methods have been proposed for the purpose of improving the quality of the subscale.
For example, Japanese Patent Application Laid-Open No. 50-71526 discloses that the surface of the final cold-rolled plate before decarburization and primary recrystallization annealing is pickled by 3 g / m ² or more,
A method is described in which a uniform glass coating is formed by removing surface deposits to improve adhesion. Also, JP-A-57-101673 discloses that the surface of the final cold rolling before decarburization and primary recrystallization is removed by grinding or pickling at 0.025 to 0.5 g / m ² per side to obtain a uniform surface. To obtain a film having excellent adhesion. Further, Japanese Patent Application Laid-Open No. 7-54154 discloses that after the intermediate annealing in the cold rolling step and before the deoxidization and the first recrystallization annealing, the surface layer is removed in an amount represented by the following formula: A ≧ (0.65 × B-543) × C Here, A: Surface layer to be removed (g / m ² ) B: Intermediate annealing temperature (° C.) C: Sheet thickness (mm) before removal of surface layer A uniform forsterite film is obtained. A method is disclosed.

[0009]

However, even with these methods, the quality of the subscale formed after decarburization and primary recrystallization annealing still varies, and as a result, the magnetic properties and the quality of the glass coating are not stable. In some cases, improvement was desired. The present invention advantageously satisfies the above-mentioned requirements, and by appropriately controlling the amounts of Si and O in the intermediate annealing before decarburization and primary recrystallization,
An object of the present invention is to propose an advantageous method of manufacturing a grain-oriented electrical steel sheet in which the coating quality and magnetic properties of a product are stabilized.

[0010]

Means for Solving the Problems In order to achieve the above object, the present inventors have studied the quality of the sub-scale formed after decarburization and primary recrystallization and the quality of the glass coating formed after finish annealing. Not only that, a detailed study was conducted on the surface condition of the steel sheet in each step before decarburization and primary recrystallization. As a result, it was found that the surface oxide layer after the intermediate annealing (that is, the surface oxide layer before final cold rolling) had a strong correlation with the product quality. Therefore, as a result of earnestly examining a method that can quickly and accurately evaluate the state of the surface oxide layer,
By using glow discharge spectroscopy, the desired purpose can be effectively achieved by precisely controlling the amounts of Si and O after the intermediate annealing within a predetermined range using the glow discharge spectroscopy. I got the knowledge of that. The present invention is based on the above findings.

That is, the gist of the present invention is as follows. 1. The silicon-containing steel material is hot-rolled, then cold-rolled twice with intermediate annealing, and finished to the final thickness, then decarburized in wet hydrogen, and then coated with an annealing separator In producing a grain-oriented electrical steel sheet by a series of steps of performing finish annealing after that, the amount of Si and O in the surface oxide layer of the intermediate annealed sheet, the cooling atmosphere after the intermediate annealing, grinding conditions and pickling conditions A method for producing a grain-oriented electrical steel sheet, characterized in that control is performed within a predetermined range by adjusting at least one condition.

2. In the above item 1, when the atmosphere and temperature during soaking in the intermediate annealing are within the SiO ₂ generation region, the amounts of Si and O in the surface oxide layer of the intermediate annealed plate were measured by glow discharge spectroscopy. A method for producing a grain-oriented electrical steel sheet, wherein the integrated strength ratio in the vicinity of a surface with respect to an iron part is controlled to be in a range of 1.1 to 2.3, respectively.

3. In the above item 1, when the atmosphere and temperature during soaking in the intermediate annealing are oxidizing at or above the Fe ₂ SiO ₄ generation region, the amounts of Si and O in the surface oxide layer of the intermediate annealed plate are measured by glow discharge spectroscopy. The ratio of the integrated strength of the Si and O near the surface to the steel
A method for producing a grain-oriented electrical steel sheet, wherein the grain diameter is controlled in the range of 1.2, 0.95 to 1.12.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be specifically described based on experimental results which led to the present invention. According to the glow discharge spectroscopy, the concentration profile of Si and O can be quickly obtained. FIG. 1 shows an example in which the profiles of Si and O on the surface of the intermediate annealed plate were obtained by using this glow discharge spectroscopy. As shown in the figure, in the glow discharge spectroscopy, the element concentration in the base iron and the element concentration near the surface can be obtained by one measurement. The figure shows the depth converted from the sputtering rate and the strength of the element to be measured.The integrated strength of Si and O was calculated for the vicinity of the surface and the base iron at intervals corresponding to the converted depth of 0.5 μm. .

Next, FIG. 2 shows the result of normalization using a so-called integrated intensity ratio obtained by dividing the integrated intensity of the surface of each measurement element by the integrated intensity of the ground iron. The test material used for the measurement was an intermediate annealed plate of a factory line. These steel sheets are steel types containing MnSe and Sb as inhibitor components. The annealing atmosphere and the annealing temperature during the soaking in the intermediate annealing are in a condition range where SiO ₂ is generated, and are a combination of a cooling atmosphere, a mechanical polishing and a pickling condition such as a brush roll and a grinding elastic roll after cooling. As a result, the amounts of Si and O in the surface oxide layer after the intermediate annealing were changed.

FIG. 3 additionally shows the results of a survey on the product quality of the materials shown in FIG. From the figure, according to the surface Si and O concentration of the intermediate annealed plate,
It can be seen that the product quality changes and it is necessary to control the Si and O concentrations within a predetermined range in order to obtain good product quality.

Then, the influence of the surface properties of the intermediate annealed sheet on the magnetic properties and the glass coating of the product was investigated. Nine intermediate annealed sheets (sheet thickness: 0.6 mm, inhibitor components: MnSe, Sb) in which Si and O each have the integrated strength ratio (cumulative strength of surface / cumulative strength of ground iron) shown in Table 1.
The final test specimen was finished by cold rolling to a final thickness of 0.22 mm, immersed in a degreasing bath using a commercially available alkaline degreasing bath, and subsequently electrolyzed in a 3% sodium orthosilicate aqueous solution. Degreasing was performed to attach a Si compound to the steel sheet surface. The amount of the Si compound deposited at this time was determined for each test material as Si. Next, soaking temperature: 820 ° C., soaking time: 120 seconds, atmosphere oxidizing property from heating up to soaking (P (H ₂ O) / P (H ₂ )) = 0.34, atmosphere oxidizing during soaking Sex = 0.
Under the conditions of 46, decarburization and primary recrystallization annealing were performed, and the subscale oxygen weight at this time was determined. Then, TiO ₂ : 1.5 parts by weight, based on 100 parts by weight of MgO,
A slurry to which 1.5 parts by weight of SrSO ₄ was added was applied and dried, followed by holding annealing at 850 ° C. for 40 hours in dry nitrogen, and the additional oxidation amount at this time was determined. FIG. 4 shows the obtained results.

[0018]

[Table 1]

As shown in FIG. 4, the test materials having a low additional oxidation amount are Nos. 4 to 6, and the other test materials have a large additional oxidation amount. An increase in the amount of additional oxidation adversely affects the formation behavior of forsterite and leads to oxidation and decomposition of the inhibitor, so that magnetic properties are likely to deteriorate. The susceptibility to this oxidation depends on the quality of the subscale generated by the charcoal / primary recrystallization annealing.
In the test materials Nos. 1 to 3, the amount of additional oxidation increased because the oxygen weight of the subscale was low. In addition, test material No. 7
No. 9 to 9 have not only a high electrolytic electrodeposition amount but also a very high sub-scale oxygen basis weight. In addition, although the sub-scale has a high basis weight of oxygen, the sub-scale has a low additional oxidation resistance, so the amount of additional oxidation is also increasing.

Then, the inventors next investigated the factors that change the subscale quality after decarburization / primary recrystallization annealing and the amount of additional acid during finish annealing. As a result, the removal of the Si layer of the intermediate annealed plate was increased in the test materials No. 1 to 3, and a large amount of the surface oxide remained after the intermediate annealing in the test materials No. 7 to 9. And these were found to be the causes of the deterioration of the product quality. This can be evaluated by the integrated intensity ratio between the surface of Si and O and that of ground iron, which is obtained by glow discharge spectroscopy of the intermediate annealed plate. In addition,
Test materials Nos. 7 to 9 are disadvantageous in that defects in the glass coating are apt to occur because the oxygen content of the subscale is very high.

As described above, if the residual amount of the surface oxide layer of the intermediate annealed sheet increases, the properties of the steel sheet surface before the decarburization / first recrystallization annealing deteriorate. That is, the surface of the steel sheet is roughened because the surface oxide layer of the intermediate annealed sheet is rolled while being thick, and not only the dirt is adhered but also the Si electrodeposited during electrolytic degreasing.
Since the amount of the compound increases, the amount of oxygen in the subscale tends to increase. Such an increase in the basis weight of oxygen or an uneven increase in the longitudinal and width directions of the coil adversely affects the formation behavior of the forsteritic glass coating during the finish annealing, and the coating in which the coating locally lacks in a dot-like manner. The frequency of occurrence of defects increases.

As described above, since the surface properties of the intermediate annealed sheet affect the quality of the next step, it is important to control the surface properties of the intermediate annealed sheet. Since the glow discharge spectroscopy used in the present invention is simple and has a high speed, it is extremely effective in quickly checking the line condition fluctuation and the surface condition of the steel sheet.

Here, when the intermediate annealing is performed under the condition that the annealing atmosphere and the annealing temperature at the time of soaking generate SiO ₂ , the amounts of Si and O in the surface oxide layer of the intermediate annealed plate are determined by glow discharge spectroscopy. It is necessary to control in the range of 1.1 to 2.3, respectively, by the integrated intensity ratio measured by the method. This is because, as shown in FIG.
If it is less than 1.1, the magnetic properties will be degraded, while 2.
If it exceeds 3, the quality of the glass coating is deteriorated.

Next, the case where the annealing atmosphere and the soaking temperature at the time of soaking in the intermediate annealing are oxidizing at or above the Fe ₂ SiO ₄ formation region will be described. In addition, AlN was used as a main component of the inhibitor. The elemental profiles of Si and O of the intermediate annealed sheet were obtained by glow discharge spectroscopy, and the Si
FIG. 5 shows the results obtained by calculating the integrated intensity of O and O, and thus the integrated intensity ratio, and normalizing using the obtained integrated intensity ratio. Note that Si, O in the surface oxide layer after the intermediate annealing
Was varied in various ways by a combination of cooling atmosphere, mechanical polishing and pickling conditions such as a brush roll and a grinding elastic roll after cooling.

FIG. 6 additionally shows the results of a survey on the product quality of the materials shown in FIG. From the figure, it can be seen that the surface Si, O concentration of the intermediate annealed plate has a suitable range for improving the product quality. Then, next, the influence of the surface properties of the intermediate annealed sheet on the magnetic properties and glass coating of the product was investigated. Nine intermediate annealed plates (sheet thickness: 1.5 mm, inhibitor main component: AlN, S) in which Si and O each have an integrated strength ratio shown in Table 2
Using b) as a test material, cold rolling is used to final thickness: 0.22mm
After immersion in a degreasing bath using a commercially available alkaline degreasing bath, soaking temperature: 840 ° C, soaking time: 120 seconds, and oxidizing property (P ( H ₂ O) /
P (H ₂ )) = 0.38, oxidizing property at soaking (P (H ₂ O) / P (H ₂ )) =
Under the conditions of 0.42, decarburization and primary recrystallization annealing were performed. This decarburized annealed plate is placed in a hydrochloric acid solution having a concentration of 5% and a liquid temperature of 60 ° C. for 60 minutes.
After immersion for 2 seconds, the acid dissolution weight loss was determined from the sample weight before and after immersion. FIG. 7 shows the obtained results together with the oxygen basis weight.

[0026]

[Table 2]

As shown in FIG. 7, the test materials having a low acid dissolution loss are Nos. 14 to 16, and the other test materials have a large acid dissolution loss. An increase in the acid dissolution weight loss adversely affects the formation behavior of forsterite and leads to oxidation and decomposition of the inhibitor and overnitrification during finish annealing, so that magnetic properties are likely to deteriorate. The magnitude of the acid dissolution loss depends on the physical properties of the subscale quality generated by decarburization and primary recrystallization annealing. Then, next, as a result of investigating the cause of the increase in the amount of acid dissolved in the decarburized annealed sheet, it was found that in the test materials No. 11 to 13, the de-Si layer of the intermediate annealed plate increased, From 17 to 19, it was found that a large amount of surface oxide remaining after the intermediate annealing was the cause of quality deterioration.

As described above, as described above, when the removal of the Si layer increases or the residual amount of the surface oxide increases, the formation behavior of the forsterite glass film during the finish annealing deteriorates. Therefore, it is necessary to control the surface properties of the intermediate annealed sheet so that such adverse effects do not occur. Here, when the annealing atmosphere and the annealing temperature at the time of soaking are oxidizing at or above the Fe ₂ SiO ₄ generation region, the amounts of Si and O in the surface oxide layer of the intermediate annealed plate are measured by glow discharge spectroscopy. 0.7 to 1.2, respectively.
, 0.95 to 1.12. This is because, as shown in Fig. 6, when the integrated intensity ratio of Si and O is less than 0.7 and 0.95, respectively, or exceeds 1.2 and 1.12, not only the deterioration of the glass film but also the magnetic properties This is because of the deterioration of.

It should be noted that Si, obtained by glow discharge spectroscopy,
It is preferable to set the depth, the integration time (integrated depth), the measurement area, and the like when obtaining the integrated strength of the surface and the ground iron from the O profile, respectively, according to the target material.

Next, a description will be given of a preferred range of the component composition of the raw material for an electrical steel sheet, which is the subject of the present invention. C: 0.02 to 0.10 wt% C is an element effective for improving the structure, but if it is out of the above range, it becomes difficult to obtain a good texture.

Si: 2.0-4.5 wt% If the Si content is less than 2.0 wt%, the effect of reducing eddy current loss decreases, while if it exceeds 4.5 wt%, the cold rolling property is impaired.

[0032] In addition to these components, an inhibitor-forming component is contained. MnS and / or Mn as inhibitors
When using Se, Mn: 0.03 to 0.1 wt%, S + Se: 0.01
To 0.03 wt%. On the other hand, when AlN is used as an inhibitor, Al: 0.01 to 0.04 wt%, N: 0.0050 to 0.0120
wt%. This is because if the content is lower than the above range, the effect as an inhibitor is insufficient, while if it is high, the secondary recrystallization becomes unstable. In addition to these, Cu, Sn, Sb, Ge, Mo, Te, Bi, P, V and
Nb can be applied, and each inhibitor can be used alone or in combination.

[0033]

【Example】

Example 1 A material for a grain-oriented electrical steel sheet in which the inhibitor is MnSe or Sb (C: 0.039 wt%, Si: 3.4 wt%, Mn: 0.07 wt%, Se:
0.020 wt%, Sb: 0.024 wt%, S: 0.002 wt%) and 2.
Hot-rolled to 0 mm, homogenized annealing at 1000 ° C for 30 seconds, rolled to a thickness of 0.6 mm by primary cold rolling, and then subjected to intermediate annealing at 950 ° C for 60 seconds (SiO ₂ generation conditions). did. The oxide layer formed on the steel sheet surface during the intermediate annealing was removed under the conditions of pickling, pickling + brush roll polishing, and pickling + elastic roll polishing. The amount of surface removal was changed by changing the pickling concentration / temperature, the number of abrasive grains for brush roll polishing and elastic roll polishing, the rotation speed, and the like. Next, the Si and O profiles of the intermediate annealed plate were measured by glow discharge spectroscopy, and the integrated strengths of the measured elements were determined for the vicinity of the surface and the ground iron at intervals corresponding to a reduced depth of 0.5 μm.

Next, after finishing to a final sheet thickness of 0.22 mm by secondary cold rolling, the sheet is heated to 830 ° C., 120 in a wet hydrogen atmosphere.
Seconds of decarburization and primary recrystallization annealing were performed. Then, MgO: 10
After applying an annealing separator containing 2 parts by weight of TiO _{2 and} 1.5 parts by weight of SrSO ₄ with respect to 0 parts by weight, secondary recrystallization annealing at 845 ° C. for 50 hours, followed by purification annealing at 1180 ° C. for 5 hours Was given. Table 3 shows the results obtained by examining the glass film adhesion / uniformity and the magnetic properties (W _17/50 , B ₈ ) of the steel sheet thus obtained. The adhesion of the glass coating was indicated by the minimum diameter of the round bar at which the steel sheet was wound around round bars having various diameters and the coating did not peel off.

[0035]

[Table 3]

As is apparent from the table, by controlling the integrated intensity ratio of Si and O obtained by glow discharge spectroscopy of the intermediate annealed plate within the proper range of the present invention, both the glass coating and the magnetic properties are extremely high. Good results could be obtained. Regardless of the method of removing the surface oxide layer in the intermediate annealing, glow discharge spectroscopic analysis is performed regardless of a method such as pickling, pickling + polishing with a brush roll containing abrasive grains, or pickling + mechanical polishing with an elastic roll containing abrasive grains and a disk. Required by
It can be seen that good results can be obtained if the integrated intensity ratio of Si and O is within a predetermined range.

Example 2 Material for grain-oriented electrical steel sheet whose inhibitor is AlN, Sb (C: 0.070 wt%, Si: 3.3 wt%, Mn: 0.07 wt%, Se:
0.023 wt%, Sb: 0.024 wt%, S: 0.002 wt%, sol.A
l: 0.023 wt%, N: 0.0083 wt%), hot-rolled to 2.4 mm, homogenized annealing at 1000 ° C for 30 seconds, rolled to a thickness of 1.5 mm by primary cold rolling, and then 1100 ° C , 90 seconds of intermediate annealing. The oxidizing soaking zone of intermediate annealing Fe ₂ SiO ₄ or Fe
The oxide layer formed on the steel sheet surface during the intermediate annealing is defined as the range in which O 2 is generated. Pickling, pickling + brush roll polishing, pickling +
It was removed under each condition of elastic roll polishing. The amount of surface removal was changed by changing the pickling concentration / temperature, the number of abrasive grains for brush roll polishing and elastic roll polishing, the rotation speed, and the like. Then, the Si and O profiles of the intermediate annealed sheet were measured by glow discharge spectroscopy, and the converted depth was 2.0 μm.
The integrated intensities of the measured elements were obtained for the vicinity of the surface and the ground iron portion at intervals corresponding to.

Next, after finishing to a final sheet thickness of 0.22 mm by secondary cold rolling, the sheet is heated to 840 ° C., 120 in a wet hydrogen atmosphere.
Seconds of decarburization and primary recrystallization annealing were performed. Then, MgO: 10
After applying an annealing separator containing 10 parts by weight of TiO _{2 and} 3 parts by weight of Sr (OH) ₂ with respect to 0 parts by weight, first holding annealing is performed at 850 ° C. for 15 hours, and then 850 ° C. to 1150 The temperature was raised to 12.5 ° C. in a mixed atmosphere of nitrogen and hydrogen at a heating rate of 12.5 ° C./h, followed by purification annealing at 1180 ° C. for 5 hours in a hydrogen atmosphere. Table 4 shows the results of examining the glass coating adhesion / uniformity and magnetic properties (W _17/50 , B ₈ ) of the steel sheet thus obtained. The adhesion of the glass coating was indicated by the minimum diameter of the round bar at which the steel sheet was wound around round bars having various diameters and the coating did not peel off.

[0039]

[Table 4]

As is clear from the table, when the integrated intensity ratio of Si and O determined by glow discharge spectroscopy of the intermediate annealed plate satisfies the proper range of the present invention, excellent glass coating and magnetic properties are obtained. Could be obtained.

[0041]

As described above, according to the present invention, by controlling the amounts of Si and O in the surface oxide layer of the intermediate annealed sheet to a predetermined range, a grain-oriented electrical steel sheet having excellent glass coating properties and magnetic properties can be stabilized. Can be obtained.

[Brief description of the drawings]

FIG. 1 shows an intermediate annealed sheet obtained by glow discharge spectroscopy.
It is a figure which shows the method of calculating | requiring the integrated intensity | strength of the surface of a Si, O profile and a measurement element, and a ground iron.

FIG. 2 is a graph showing the integrated intensity ratio between the surface of Si and O and the ground iron obtained by glow discharge spectroscopy of an intermediate annealed plate sampled from a factory line.

FIG. 3 is a view showing product characteristics of the intermediate annealed plate shown in FIG. 2;

Fig. 4 Electrodeposition amount of Si compound after electrolytic degreasing of test material,
It is a figure which shows the amount of oxygen basis after primary recrystallization annealing, and the amount of additional oxidation during finish annealing.

FIG. 5 is a diagram showing the integrated intensity ratio between the surface of Si and O and the ground iron obtained by glow discharge spectroscopy of an intermediate annealed plate sampled from a factory line.

FIG. 6 is a view showing product characteristics of the intermediate annealed plate shown in FIG.

FIG. 7 is a view showing an oxygen basis weight and an acid dissolution loss after decarburization and primary recrystallization annealing of a test material.

Claims (3)

[Claims] Claims 1. A silicon-containing steel material is hot-rolled and then cold-rolled twice with intermediate annealing to a final thickness.
Then, after performing decarburizing annealing in wet hydrogen, to produce a grain-oriented electrical steel sheet by a series of steps of applying an annealing separator and then performing final annealing, Si and Si in the surface oxide layer of the intermediate annealed sheet A method for producing a grain-oriented electrical steel sheet, wherein the amount of O is controlled to a predetermined range by adjusting at least one of a cooling atmosphere after intermediate annealing, a grinding condition, and a pickling condition. 2. The method according to claim 1, wherein the amount of Si and O in the surface oxide layer of the intermediate annealed plate is measured by glow discharge spectroscopy when the atmosphere and the temperature during the soaking of the intermediate annealing are within the SiO ₂ generation region. A method for producing a grain-oriented electrical steel sheet, characterized in that the integrated strength ratios of Si and O in the vicinity of the surface with respect to the iron base are each controlled in the range of 1.1 to 2.3. 3. The method according to claim 1, wherein when the temperature and the atmosphere during the soaking of the intermediate annealing are oxidizing in the Fe ₂ SiO ₄ generation region or higher, the amounts of Si and O in the surface oxide layer of the intermediate annealed plate are determined. The integrated intensity ratio of Si and O in the vicinity of the surface with respect to the base iron part measured by glow discharge spectroscopy.
A method for producing a grain-oriented electrical steel sheet, wherein the grain diameter is controlled in the range of 1.2, 0.95 to 1.12.