JP2005069930A - Manufacturing method for directional electromagnetic steel plate having excellent coating adhesiveness - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an evaluation method for measuring a sputtering time up to ferrite on the steel plate surface by rf-GDS, and the absorbance by FT-IR in the stage after decarbonization annealing in a manufacturing process for a directional electromagnetic steel plate, evaluating beforehand coating adhesiveness in the final product stage, and improving the quality of the final product or improving the yield, and a manufacturing method for the directional electromagnetic steel plate having excellent coating adhesiveness using the evaluation method. <P>SOLUTION: In the evaluation method for the directional electromagnetic steel plate, the sputtering time up to the ferrite is measured on the steel plate surface by a high-frequency glow discharge emission spectral analysis method (rf-GDS) in the stage after decarbonization annealing of the directional electromagnetic steel plate, and the peak of each infrared transmittance of Fe<SB>2</SB>SiO<SB>4</SB>, SiO<SB>2</SB>and FeSiO<SB>3</SB>on the steel plate surface is measured by a Fourier transform infrared absorption spectrum method (FT-IR), and the absorbance of each compound is calculated, and the ratio of the absorbance of Fe<SB>2</SB>SiO<SB>4</SB>to the total of the absorbance of each compound is calculated, and the coating adhesiveness of the final product of the directional electromagnetic steel plate is evaluated from the acquired sputtering time and the ratio of the absorbance of Fe<SB>2</SB>SiO<SB>4</SB>. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention measures the spattering time to the base iron in rf-GDS at the stage after decarburization annealing in the manufacturing process of the grain-oriented electrical steel sheet, and measures the steel sheet surface by FT-IR. The present invention relates to an evaluation method for evaluating film adhesion at a product stage in advance to improve the quality of a final product or to improve yield, and a method for producing a grain-oriented electrical steel sheet having excellent film adhesion using the evaluation method.

In the grain-oriented electrical steel sheet, an oxide film containing SiO ₂ as a main component is generated in the process of decarburizing and pure. Thereafter, a forsterite (Mg ₂ SiO ₄ ) film (glass film) is produced, and further a tension film is coated. However, it is known that the state of formation of an oxide film containing SiO ₂ as a main component affects the adhesion of the tension film.

Conventionally, a pure separation agent before being applied to a steel plate is mixed with KBr powder to form a tablet, and an infrared absorption spectrum of the KBr tablet is measured, and a hydration degree (annealing separation agent) is measured from the area or height of the absorption peak at 3700 cm ^−1. Change in weight before and after heating) was evaluated for the film adhesion of the grain-oriented electrical steel sheet obtained by forming a film with the annealing separator (see Patent Document 1). However, there is a problem that it takes time to pre-process the sample, and it takes time to obtain an analysis result. Further, in infrared spectroscopic measurement, there is an example in which the amount of oxide film formed on the steel sheet surface is estimated from the reflectance peak intensity ratio of 995 cm ⁻¹ (see Patent Document 2), but the film adhesion is not evaluated. Furthermore, in glow discharge optical emission spectrometry, there is an example in which the magnetic properties of the oxide layer on the steel sheet surface are evaluated by the integrated strength of the Si intensity / Mn intensity ratio (see Patent Document 3), but the coating adhesion is not evaluated. There was a problem that the insulating coating was charged and normal measurement was not possible.
JP 2002-90300 A Japanese Patent Laid-Open No. 3-108639 JP-A-11-269543

  In view of the above-mentioned problems in the prior art, the present invention measures the oxide film after decarburizing and purifying in the production process of grain-oriented electrical steel sheets using rf-GDS and FT-IR, and determines the sputter time and absorbance ratio values. In addition, the coating adhesion is evaluated before the coating is formed on the steel sheet, and the grain-oriented electrical steel sheet having excellent coating adhesion is manufactured by controlling the manufacturing conditions of the decarburized annealing plate according to the evaluation. With the goal.

That is, the present invention provides the following inventions.
(1) At the stage after decarburization annealing in the production process of grain-oriented electrical steel sheets, the surface of the steel sheet is measured by high-frequency glow discharge optical emission spectrometry (rf-GDS), and the sputter time to the ground iron is measured, and Fourier transform By measuring the infrared transmittance peak of Fe ₂ SiO ₄ , SiO ₂ and FeSiO _{3 on} the steel sheet surface by infrared absorption spectroscopy (FT-IR), the absorbance of each compound is calculated, and the total absorbance of each compound is calculated. Fe ₂ calculates a ratio of the absorbance of the SiO _4, from the ratio of the absorbance of the resulting sputtering time and Fe ₂ SiO _4, the evaluation method of the grain-oriented electrical steel sheet to evaluate the coating adhesion of the final product of the grain-oriented electrical steel sheet.
(2) The ratio of the sputtering time and the absorbance of Fe ₂ SiO ₄ obtained in (1) above is compared with the decarburization annealing process step or the previous process conditions, and the steel sheet is controlled by controlling at least one process condition. A method for producing a grain-oriented electrical steel sheet that is processed to produce a decarburized and annealed sheet for grain-oriented electrical steel sheets, and thereafter to produce a grain-oriented electrical steel sheet having excellent coating adhesion by surface coating.

(3) The sputtering time measured by the evaluation method described in (1) above and the absorbance ratio of Fe ₂ SiO ₄ are as follows: the absorbance ratio is 30%, the sputtering time is 66 seconds, the absorbance ratio is 65%, and the sputtering time is 72%. A straight line connecting two points including a straight line connecting two points that are seconds, lower than the straight line, and having an absorbance ratio of 41% and a sputtering time of 55 seconds, and an absorbance ratio of 65% and a sputtering time of 68 seconds. A decarburized and annealed plate for grain-oriented electrical steel sheets, which is included in a region above the straight line.
(4) A grain-oriented electrical steel sheet excellent in film adhesion obtained using the decarburized and annealed sheet for grain-oriented electrical steel sheet according to (3) above.
(5) a sputter time measuring machine that measures the sputter time to the base metal by high-frequency glow discharge optical emission spectrometry (rf-GDS) at the stage after decarburization annealing in the manufacturing process of the grain-oriented electrical steel sheet; An infrared source for irradiating the steel sheet surface with infrared rays; a spectroscope and a detector for detecting infrared rays reflected from the steel sheet; and Fe ₂ SiO ₄ , SiO ₂ , FeSiO obtained by Fourier transform infrared absorption spectroscopy (FT-IR) ₃ is calculated from each peak of the infrared transmittance of No. _{3, and} the ratio of the absorbance of Fe ₂ SiO ₄ to the total of the respective absorbances is calculated. From the calculated value and the sputtering time, the final product of the grain-oriented electrical steel sheet is calculated. An apparatus for evaluating film adhesion of a grain-oriented electrical steel sheet having a data processing apparatus for evaluating film adhesion.

The evaluation method of the present invention measures the sputter time to the ground iron in rf-GDS, which can measure the insulating coating on the steel sheet surface without charging at the stage after decarburization annealing in the production process of the grain-oriented electrical steel sheet, and The Fe ₂ SiO ₄ , SiO ₂ , and FeSiO ₃ in the oxide film on the steel sheet surface were measured by FT-IR, and the ratio of the absorbance of Fe ₂ SiO ₄ to the total of the respective absorbances was determined, and the correlation with the film adhesion of the final product Therefore, the quality of the final product can be determined before the coating is formed on the steel sheet, which is suitable for improving the yield of the final product. Moreover, it is possible to manufacture the grain-oriented electrical steel sheet excellent in film adhesiveness by controlling the decarburizing and pure treatment conditions using this method.

Hereinafter, the present invention will be described in more detail, but the present invention is not limited to these embodiments.
[1] The evaluation method of the present invention measures the sputter time to the base iron in rf-GDS, which can measure the insulating coating on the steel sheet surface without charging at the stage after decarburization annealing in the manufacturing process of the grain-oriented electrical steel sheet. and, and, a transmittance of infrared light _{Fe 2 SiO 4, SiO 2,} FeSiO 3 formed on the steel sheet surface was measured by FT-IR, and calculates each absorbance, _Fe 2 SiO ₄ to the sum of the absorbances The ratio of the absorbance is calculated. This is a method for evaluating the film adhesion of the final product of the grain-oriented electrical steel sheet from the ratio of the obtained sputtering time and the absorbance of Fe ₂ SiO ₄ . Here, the timing of the measurement may be after the decarburization annealing is finished and cooled to room temperature, or any time during the decarburization annealing that can be considered that the predetermined process of the decarburization annealing is substantially finished. It may be a stage.

In general, the production process of grain-oriented electrical steel sheet is performed by hot-rolling a slab containing Si: 2.5 to 4.0% by mass, and then performing annealing and one or more times of cold rolling including intermediate annealing to obtain a final thickness. It is said. Next, in a continuous annealing furnace, decarburization annealing is performed in a mixed atmosphere of hydrogen gas or hydrogen gas and nitrogen gas, and along with decarburization, primary recrystallization and an oxide film mainly composed of SiO ₂ are generated. Thereafter, an annealing separator made of MgO or the like is suspended in water to form a slurry, which is applied onto a steel plate, dried, wound into a coil, and subjected to final finish annealing, forsterite (Mg ₂ SiO ₄ ) A film (glass film) is prepared, and further a tension film mainly composed of a phosphate system is coated, and flattened and annealed to obtain a final product.

The inventors of the present invention measured the sputtering time to the ground iron in rf-GDS that can measure the insulating coating on the steel sheet surface after decarburization annealing without charging, and Fe ₂ SiO ₄ , SiO ₂ , Each absorbance is calculated from the FT-IR peak of FeSiO ₃ (a peak indicating infrared transmittance), and the ratio of the absorbance of Fe ₂ SiO ₄ to the total of the absorbances is calculated. It was invented that the film adhesion of the final product of the heat-resistant electrical steel sheet can be evaluated.
If this correlation is used, it is possible to evaluate whether the final product has good or poor film adhesion or suitability for manufacturing conditions at the stage of decarburized annealing plate before film formation.

  The sputtering time and the absorbance ratio used for evaluation can be determined by the method exemplified below, but are not limited to this method. For example, a standard material with a known composition on the surface of the steel sheet after decarburization annealing and a sputtering time and an absorbance ratio with various corrections using values measured by other measurement methods using pure substances for comparison are calculated. May be. The measurement wavelength of the FT-IR peak (infrared transmittance) is not particularly limited because it does not directly affect the absorbance ratio, but can be selected from the range of 450 to 1400 cm. The FT-IR peak may be measured at several points on the steel sheet surface and the average value may be calculated. The sputtering time and the absorbance ratio may be measured at the same place on the surface of the steel sheet, but each measurement may be performed separately from several predetermined points and averaged.

  FIG. 1 is a view showing an Fe profile in rf-GDS measurement. In FIG. 1, the time from the steel sheet surface to the half value of the maximum value and the minimum value of the profile on the side rail is defined as the sputter time to the side rail.

On the other hand, FIG. 2 is a figure which shows the peak of the transmittance | permeability in FT-IR measurement. In FIG. 2, a reference line de connecting the bases of a specific peak is drawn, and an intersection of a perpendicular line passing through the peak b and the reference line de is defined as a, and an intersection of the horizontal axes is defined as c. At this time, assuming that the transmittance (%) on the vertical axis is ac and bc, the absorbance A is

A = log (ac / bc) --- (1)

It is expressed. Therefore, assuming that the absorbance of each of Fe ₂ SiO ₄ , SiO ₂ and FeSiO ₃ is Al, A2 and A3, the absorbance ratio B (%) to the total absorbance of Fe ₂ SiO ₄ is

B = Al × 100 / (Al + A2 + A3) −−− (2)

It is expressed.

FIG. 3 shows a cross section of the steel sheet at the stage after decarburization annealing in the manufacturing process of the grain-oriented electrical steel sheet. The oxide film is mainly composed of SiO ₂ and additionally contains Fe ₂ SiO ₄ and FeSiO ₃ . Obtain the infrared transmittance of these three compounds, obtain the ratio of the absorbance of Fe ₂ SiO ₄ to the total absorbance from the absorbance of each compound calculated as described above, A method of evaluating good and poor film adhesion of the final product by measuring the sputtering time is preferable. As an example of the evaluation method, a set of sputtering time and absorbance ratio is plotted as an XY axis, and then a film is formed to evaluate the film adhesion. If the evaluation is poor or inferior, it is indicated by x. Since the evaluation circle is divided from the evaluation circle in the range on the XY plane, the sputter time of the steel sheet surface to be evaluated next after decarburization annealing. And the absorbance ratio, and plotted on the same XY plane, it can be determined whether the evaluation is ◯ or X in the area where the point is located.

[2] The method for producing a grain-oriented electrical steel sheet according to the present invention compares the sputtering time and the absorbance ratio obtained as described above with a decarburization annealing process or a process condition before the at least one process condition. Is a method for producing a grain-oriented electrical steel sheet with excellent film adhesion by controlling the steel sheet.
As the decarburization annealing treatment conditions, it is possible to control the treatment conditions such as the degree of vacuum before the gas inflow, the flow rate of hydrogen gas, or the mixed atmosphere of hydrogen gas and nitrogen gas, the ratio, the dew point or the temperature of the decarburization treatment, and the time. it can.

Other processing conditions include conditions such as the amount of Si in the slab or the amount of other additive elements or impurity elements, slab hot rolling, annealing conditions and times, cold rolling conditions and times, and final plate thickness.
Further, in the case where various processing conditions are changed in advance, the variation factors of the processing conditions can be grasped by investigating the change in the evaluation width of each sputtering time and each absorbance ratio.
By using the production method of the present invention, various production conditions such as decarburization annealing treatment can be evaluated before obtaining the final product, and various production conditions are controlled to produce a grain-oriented electrical steel sheet with excellent film adhesion. Is possible.
The production method of the present invention may be a method of controlling at least one processing condition by evaluating using the evaluation method of the present invention for each product type, product number, and lot. After the processing conditions are determined by the above, a manufacturing method in which the manufacturing is performed under the determined processing conditions and is not evaluated is also included.

In addition, the value of the ratio of absorbance of Fe ₂ SiO ₄ after decarburization annealing is 30%, including a straight line connecting two points where the sputtering time is 66 seconds, and when 65% is 72 seconds, below the straight line, and If the region includes a straight line connecting two points, the sputter time being 55 seconds at 41% and 68 seconds at 65%, as long as the region is above the straight line, as shown in the examples described later, A grain-oriented electrical steel sheet having excellent film adhesion of a tensile film is obtained.

Therefore, the decarburized annealing plate showing the absorbance ratio of Fe ₂ SiO ₄ and the sputtering time in such a region is useful as an intermediate for producing a grain-oriented electrical steel sheet having excellent coating adhesion. If the evaluation method of the present invention is used, the steel plate surface after decarburization annealing is measured by the evaluation method of the present invention, and only those whose sputtering time and absorbance ratio indicate numerical values within a predetermined region are selected, and thereafter If a film is formed on a steel plate, the yield of the final product can be dramatically increased.
Using the decarburized and annealed plate showing the sputtering time and absorbance ratio of the present invention in the above-mentioned range, a grain-oriented electrical steel sheet having excellent coating adhesion can be obtained by performing the steps after the application of the annealing separator to obtain the final product. .

[3] Next, the evaluation apparatus for grain-oriented electrical steel sheets according to the present invention will be described.
4 and 5 show one embodiment of the apparatus for evaluating the film adhesion of the grain-oriented electrical steel sheet of the present invention, but the evaluation apparatus of the present invention is not limited to this.
In FIG. 4, 1 is a steel plate sample after decarburization annealing, 2 is a glow discharge source, these form a glow discharge tube 10 together with the lens 4, and the steel plate sample 1 is a cathode. The glow discharge tube 10 is controlled by a glow discharge control system 13. On the other hand, glow discharge is performed by a glow discharge unit 15 having a cooling system, a gas pressure control RF power source, and a DC power source. Reference numeral 3 denotes light emitted when a part of surface atoms is emitted into the plasma by ion sputtering hitting the sample, is repeatedly excited with collision with other atoms, and is deexcited. The light 3 passes through the lens 4 and enters the spectroscope 12 in the vacuum ultraviolet measurement vacuum vessel 11. The light that enters the spectroscope 12 is diffracted by the diffraction grating 6 and separated, and is detected by a detector such as the photomultiplier tube 8 from the exit slit 7. The detected light signal enters the light intensity measurement circuit 16 through the electric conductor 9 and is measured. The measured data is processed by the data processing device 17 as the amount of change in the depth direction in the steel sheet of at least one element amount, and the sputtering time is calculated. The data processing apparatus includes a control circuit, a local computer, and a personal computer, and may control the glow discharge system 13, the glow discharge unit 15, and the vacuum control system 18.

In FIG. 5, 21 is an infrared source, 22 is an infrared ray, 23, 24 and 27 are mirrors, 25 is a sample, 26 is a reflected infrared ray, 28 is a spectroscope and a detector, and 29 is a data processing device.
The infrared rays 22 generated from the infrared source 21 are reflected by the mirrors 23 and 24, are incident on the steel plate surface 25 after decarburization and are reflected, are reflected, and the reflected infrared rays 26 are reflected by the mirror 27, and the spectrometer and detector 28 are reflected. The data is processed by a data processing device 29 such as a general-purpose computer or a calculation chip, and the absorbance is calculated, and the ratio of the specific substance to the total absorbance is obtained. The quality of film adhesion is evaluated from these two data.

Measurement samples 1 to 21 were prepared as follows. As decarburization annealing pretreatment, 0.05 μm or more of the low Si concentration portion formed on the surface by intermediate annealing is removed by pickling, and 0.01 to 0.5 g / m ^{2 of} oxide generated during intermediate annealing is left. The surface roughness was controlled within the range of 0.1 to 0.7 μm, and the deposition of the Si compound was appropriately changed. Then, as decarburization annealing conditions, in a hydrogen atmosphere, the dew point is 30 to 70 ° C., the soaking temperature is 820 to 880 ° C., the soaking time is 80 to 130 seconds, and during heating, the soaking is held and reduced. atmosphere oxidizing _{(pH 2} 0 / pH 2) a 0.09~0.70,650 ℃ 1~30 ℃ heating rate up to the point where lower 10 ° C. for soaking temperature from / sec, a reduction treatment time It was changed appropriately from 5 to 150 seconds.

Using this sample, the steel plate surface after decarburization annealing was measured using the evaluation apparatus shown in FIGS. The rf-GDS measurement was performed on a System 3860 type rf-GDS manufactured by Rigaku Denki Kogyo Co., Ltd. under the conditions of a high frequency power of 40 W, an Ar gas flow rate of 250 cc / min, and a sputtering rate of 38 nm / s (Fe conversion). In addition, FT-IR measurement was performed by integrating and measuring 16 times in the air under the condition of an infrared incident angle of 70 ° in a 1600-type FT-IR manufactured by Perkin Elmer Co., and performing a CO ₂ peak removal treatment after the measurement.

One example of the measurement result of the transmittance up to 450 to 1400 cm ⁻¹ as a result of measuring the infrared transmittance is shown in FIG. 6. In the figure, the absorbance of Fe ₂ SiO ₄ and SiO ₂ was determined using xy as a reference line. Further, the absorbance of FeSiO ₃ was determined using uv as a reference line. Incidentally, x and y are respectively ^{1300 cm} -1, and the highest position of the transmittance of 850 cm ^-1 vicinity. Since it became clear that this was a position with little fluctuation in measurement, it was set as a reference position. The results of measurement samples 1 to 21 are shown in Table 1.

after that,
1) MgO: An annealing separator in which 2 parts by mass of TiO ₂ is added to 100 parts by mass is suspended in water to form a slurry, which is applied to a steel sheet at 10 g / m ² (both sides), dried, and then coiled Rolled up into a shape,
2) After holding at 880 ° C. for 50 hours, followed by purification annealing at 1200 ° C. for 10 hours to produce a forsterite (Mg ₂ SiO ₄ ) coating (glass coating).
3) A tension film having a composition of 50 parts by mass of magnesium phosphate, 45 parts by mass of colloidal silica, 4.5 parts by mass of chromic anhydride, and 0.5 parts by mass of alumina powder was coated at 10 g / m ² (both sides).
4) A final product was obtained by planarizing and annealing at 800 ° C. for 3 minutes under a nitrogen atmosphere.
5) The film defect occurrence rate on the surface of the obtained grain-oriented electrical steel sheet was measured by visual observation, and compared with the sputtering time and the absorbance ratio B obtained previously. The results are shown in Table 1. In the determination, the case where the film defect occurrence rate was less than 0.02% was evaluated as “good”, and the case where it was 0.02% or more was indicated as “bad”. FIG. 7 shows a diagram with B as the horizontal axis and sputtering time as the vertical axis.
In addition, the film defect occurrence rate measured visually is divided into 10 in the width direction of the coil of the grain-oriented electrical steel sheet and 1 m in the longitudinal direction, and dot film defects, color unevenness, It is a value obtained by evaluating defects such as peeling by area ratio.

From FIG. 7, including the straight line connecting the two points of the sputtering time of 66 seconds when the value of the absorbance ratio B (%) of Fe ₂ SiO ₄ is 30% and 72 seconds when the value is 65%, below the straight line, In addition, the determination is good in a region including a straight line connecting two points, in which the sputtering time is 55 seconds at 41% and 68 seconds at 65%. Therefore, if the sputtering time to the ground iron in rf-GDS on the steel sheet surface after decarburization annealing is measured, and the absorbance ratio of Fe ₂ SiO _{4 on} the steel sheet surface is set within a predetermined range, coating failure of the final product will occur. It was predicted that the rate could be good, and it was possible to identify that the final product was defective.

The optimum processing conditions for the obtained grain-oriented electrical steel sheet were as follows.
As the decarburization pure pretreatment conditions, a portion having a low Si concentration generated on the surface by intermediate annealing is removed by 0.1 μm or more by pickling, and the oxide generated at the intermediate annealing is 0.01 to 0.3 g / m ^2. Remaining, the surface roughness is controlled within the range of 0.1 to 0.5 μm, and the Si compound is adhered. Subsequent decarburization annealing conditions include a hydrogen atmosphere, a dew point of 59 to 61 ° C., a soaking temperature of 820 to 840 ° C., a soaking temperature of 92 to 120 seconds, and an oxidizing atmosphere (partial pressure ratio pH _2). 0 / pH ₂ ) of 0.27 to 0.50, and the atmospheric oxidization property in soaking is 0.04 to 0.20 higher than that during heating, from 650 ° C. to 10 ° C. lower than the soaking temperature. This was a production method in which the temperature rising rate was 1.4 to 26 ° C./second, and the reduction treatment was carried out for 5 to 100 seconds at an atmospheric oxidizing property of 0.2 or less. Thereby, the grain-oriented electrical steel sheet excellent in film adhesion could be manufactured.

It is the schematic explaining 1 example which calculates | requires the electrolysis time to the ground iron by a rf-GDS measuring method from a measurement profile. It is the schematic explaining one example of how to obtain | require an absorbance from the measurement peak of the infrared transmittance by FT-IR measuring method. It is typical sectional drawing which shows the cross section in the stage after the decarburization refractory in the manufacturing process of a grain-oriented electrical steel sheet. It is a figure explaining the measuring apparatus used for the rf-GDS measuring method of the evaluation method of this invention. It is a figure explaining the measuring apparatus used for the FT-IR measuring method of the evaluation method of this invention. It is a chart which shows the transmittance | permeability of the infrared rays by the FT-IR measuring method in the wave numbers 450-1400cm < ^-1 > of the infrared rays of an Example. It is a figure which shows the relationship between B of Table 1 and sputtering time.

Explanation of symbols

1: Steel plate sample 2: Glow discharge power source 3: Light 4: Lens 5: Slit 6: Diffraction grating 7: Exit slit 8: Photomultiplier tube 9: Electrical conductor 10: Glow discharge tube 11: Vacuum container for vacuum ultraviolet region measurement 12: Spectrometer 13: Glow discharge control system 15: Glow discharge unit 16: Light intensity measuring circuit 17: Data processing device
18: Vacuum control system 21: Infrared ray source 22: Infrared ray 23, 24: Mirror 25: Sample 26: Reflected infrared ray 27: Mirror 28: Spectrometer / detector 29: Data processing device B: Absorbance ratio of Fe ₂ SiO ₄

Claims (5)

At the stage after decarburization annealing in the production process of grain-oriented electrical steel sheet, the surface of the steel sheet is measured by high-frequency glow discharge emission spectroscopy (rf-GDS), and the sputter time to the ground iron is measured, and the Fourier transform infrared absorption spectrum The peak of infrared transmittance of Fe ₂ SiO ₄ , SiO ₂ and FeSiO _{3 on} the steel sheet surface is measured by the method (FT-IR), the absorbance of each compound is calculated, and Fe ₂ SiO relative to the total absorbance of each compound calculating the ₄ ratio of absorbance, from the ratio of the absorbance of the resulting sputtering time and Fe ₂ SiO _4, the evaluation method of the grain-oriented electrical steel sheet to evaluate the coating adhesion of the final product of the grain-oriented electrical steel sheet. The ratio of the sputtering time and the absorbance of Fe ₂ SiO ₄ obtained in claim 1 is compared with the decarburization annealing process step or previous process conditions, and the steel sheet is processed by controlling at least one process condition. A method for producing a grain-oriented electrical steel sheet, in which a decarburized annealed sheet for a grain-oriented electrical steel sheet is produced, and then a surface-coated steel sheet is produced by producing a grain-oriented electrical steel sheet having excellent coating adhesion. The sputtering time measured by the evaluation method according to claim 1 and the absorbance ratio of Fe ₂ SiO ₄ are as follows: the absorbance ratio is 30%, the sputtering time is 66 seconds, the absorbance ratio is 65%, and the sputtering time is 72 seconds 2 Including a straight line connecting points, including a straight line connecting two points below the straight line and having an absorbance ratio of 41% and a sputtering time of 55 seconds, and an absorbance ratio of 65% and a sputtering time of 68 seconds. A decarburized and annealed plate for grain-oriented electrical steel sheets, which is included in the upper region.   A grain-oriented electrical steel sheet excellent in film adhesion obtained by using the decarburized annealing plate for grain-oriented electrical steel sheet according to claim 3. A sputter time measuring machine for measuring the spatter time to the iron core by high-frequency glow discharge optical emission spectrometry (rf-GDS) at the stage after decarburization annealing in the production process of grain-oriented electrical steel sheet; An infrared source for irradiating infrared rays; a spectroscope and detector for detecting infrared rays reflected from a steel plate; and infrared rays of Fe ₂ SiO ₄ , SiO ₂ , and FeSiO ₃ obtained by Fourier transform infrared absorption spectroscopy (FT-IR) Each absorbance is calculated from each peak of transmittance, the ratio of the absorbance of Fe ₂ SiO ₃ to the total of each absorbance is calculated, and the film adhesion of the final product of the grain-oriented electrical steel sheet from the calculated value and the sputtering time An apparatus for evaluating the film adhesion of a grain-oriented electrical steel sheet having a data processing apparatus for evaluating the above.

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