KR101286246B1 - Apparatus and method for miniaturizing magnetic domain of a grain-oriented electrical steel sheets - Google Patents

Abstract

The present invention relates to a magnetic domain micronization of a grain-oriented electrical steel sheet, comprising: a laser generator for generating a laser beam; Optical means for irradiating the surface of the oriented electrical steel sheet by changing the direction of the laser beam generated from the laser generator; A support trolley for contacting the directional electrical steel sheet to which the laser beam is irradiated by the optical means to impart tension; In the magnetic micronizing method of electrical steel sheet, it provides a magnetic micronizing method of a grain-oriented electrical steel sheet characterized in that the tension is applied to the grain-oriented electrical steel sheet to which the laser beam is irradiated using the support trolley. Therefore, according to the present invention, by applying a proper tension to the steel sheet using the support trolley during laser magnetic micronization treatment, it is possible to obtain an excellent iron loss improvement effect while preventing the deterioration of the magnetic flux density, and the shape of the laser beam according to the thickness of the oriented electrical steel sheet The automatic change enables continuous production of micronized electrical steel sheets in variable and high speed on-line.

Description

Apparatus and method for miniaturizing magnetic domain of a grain-oriented electrical steel sheets}

The present invention relates to the magnetic domain miniaturization of a grain-oriented electrical steel sheet used for the iron core used as a moving path of the magnetic field formed by the voltage applied to the winding in the transformer, more specifically by applying a tension to the laser irradiation portion of the grain-oriented electrical steel sheet The present invention relates to a magnetic domain micronizing apparatus and a magnetic domain micronization method of a grain-oriented electrical steel sheet capable of maximizing magnetic domain micronization effects and minimizing on-line magnetic domains.

A grain-oriented electrical steel sheet is a silicon steel (Si-Steel) exhibiting a secondary recrystallized texture in the {110} <001> azimuth parallel to the rolling direction, the basic concept of which is first proposed by NP Goss in US Patent 1965559. Since then, a new manufacturing method has been invented and introduced by many researchers to improve the iron loss characteristics.

Magnetic micronization is one of the techniques for lowering the iron loss of the grain-oriented electrical steel sheet, a technique for miniaturizing the magnetic domain in the vertical direction of the rolling by a mechanical method using a laser or a magnetic micronized roll.

Technology of irradiating a laser in a magnetic domain refining technique on the surface of the steel sheet is a continuous wave (CW; Continous Wave) CO ₂ laser, a pulsed (Pulse) CO ₂ lasers, solid-state YAG or a laser on the surface of the laser plate by means such as a Fiber laser Is investigating. Among them, continuous wave CO ₂ lasers have lower maintenance costs and larger depth of focus than pulsed CO ₂ lasers. In line micronization, it is difficult to ensure the uniformity of the laser beam irradiated onto the surface of the steel sheet due to the shaking of the steel sheet during laser irradiation.

Therefore, it is necessary to develop a technology that can prevent the damage of the insulating coating layer and the deterioration of the magnetic flux density by securing the uniformity of the laser incoming energy irradiated to the surface of the steel sheet.

In addition, there is a difference in the shape of the laser beam in which the magnetic domain miniaturization effect is maximized according to the thickness of the steel sheet in the grain size of the grain-oriented electrical steel sheet. However, there was a problem in that the magnetic domain refinement process should be temporarily stopped in order to replace the beam shaping mirror for changing the shape of the laser beam at every thickness change of the steel sheet.

The present invention has been made in view of the above-described problems of the prior art, and the object of the present invention is to maximize the effect of miniaturizing magnetic domains by applying tension to the laser irradiated portion of the steel sheet by using a supporter during laser magnetic micronization. An object of the present invention is to provide a micronized device and a micronized method for grain-oriented electrical steel sheet.

In addition, the present invention provides a magnetizing apparatus and a micronizing method of a grain-oriented electrical steel sheet capable of continuously producing the magnetic grained electrical steel sheet in a variable and high-speed on-line by automatically changing the shape of the laser beam according to the thickness of the grain-oriented electrical steel sheet There is also a purpose to provide.

In order to solve the above problems, there is provided a magnetic domain micronizing apparatus for a grain-oriented electrical steel sheet according to the present invention, comprising: a laser generating unit for generating a laser beam; Optical means for irradiating the surface of the oriented electrical steel sheet by changing the direction of the laser beam generated from the laser generator; And a supporter configured to apply tension by contacting the directional electrical steel sheet to which the laser beam is irradiated by the optical means.

The support trolley is characterized by applying a tension of 0.1-20 kgf / mm ² to the oriented electrical steel sheet by contacting the opposite side of the irradiated portion to which the laser beam of the grain-oriented electrical steel sheet is irradiated.

The magnetic domain micronizing device of the grain-oriented electrical steel sheet of the present invention is characterized in that it further comprises a drive unit for adjusting the tension by lifting or lowering the bearing block for rotatably supporting the support trolley.

The optical means includes a plurality of beam-shaped mirrors for changing the shape of the laser beam generated from the laser generator; And a mirror adjusting unit for automatically adjusting one of the plurality of beam-shaped mirrors according to the thickness of the directional electrical steel sheet.

In the magnetic domain miniaturization method of a grain-oriented electrical steel sheet of the present invention, in the grain-oriented microstructure of a grain-oriented electrical steel sheet to refine the magnetic domain by irradiating a laser beam on the surface, the grain-oriented electrical steel sheet is irradiated by the laser beam is irradiated by contacting the support to the grain-oriented electrical steel sheet It is characterized by imparting tension.

According to the present invention, the method for fine-magnetizing the grain-oriented electrical steel sheet is to apply a tension of 0.1-20 kgf / mm ² to the grain-oriented electrical steel sheet by applying tension to the opposite side of the irradiated portion to which the laser beam of the grain-oriented electrical steel sheet is irradiated. It is characterized by.

According to the present invention, the method for fine-magnetizing the grain-oriented electrical steel sheet is such that the tensile stress is 0.1 to 25 kgf / mm ² in the region of 0.2 times or more of the width of the laser beam in the longitudinal direction of the steel sheet, and in the thickness direction under the irradiation line by the laser beam. It characterized in that the compressive stress is 0.1 ~ 35kgf / mm ² in the region of 0.1 times or more of the thickness of the steel sheet.

The magnetic domain miniaturization method is characterized in that the automatic adjustment so that any one of the plurality of beam-shaped mirrors are selected according to the thickness of the oriented electrical steel sheet.

The magnetic domain micronizing method is characterized in that the distance between the irradiation lines formed on the surface of the steel sheet by the laser beam is 4.0 to 12.0mm, and the laser beam is irradiated on the surface of the steel sheet so that the inlet energy of the laser is 4500 to 7500mJ.

The magnetic domain micronization method is characterized in that there is no deterioration of the magnetic flux density compared to before magnetic domain micronization, and the iron loss improvement rate is 10% or more.

According to the present invention, by applying the tension to the steel sheet by contacting the supporter during the laser micronized micronizing process to ensure the uniformity of the laser beam irradiated to the surface of the steel plate can maximize the micronized effect. In addition, according to the present invention, by automatically changing the shape of the laser beam in accordance with the thickness of the grain-oriented electrical steel sheet it can be produced continuously fine-grained electrical steel sheet in a variable and high-speed on-line.

1 is a schematic diagram of a magnetic domain micronizing device of a grain-oriented electrical steel sheet according to an embodiment of the present invention,
Figure 2 is a schematic diagram showing the support constituting the micronizing device of the grain-oriented electrical steel sheet according to an embodiment of the present invention,
3 is a front view showing a support control and a driving unit constituting the micronizing device of the grain-oriented electrical steel sheet according to an embodiment of the present invention,
Figure 4 is a view showing the shape of the laser beam irradiated on the surface of the steel sheet by the method of magnetizing the grain-oriented electrical steel sheet according to an embodiment of the present invention.

Hereinafter, with reference to the accompanying drawings will be described a preferred embodiment of the present invention. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided so that the disclosed contents may be thorough and complete, and the technical spirit of the present invention may be sufficiently delivered to those skilled in the art.

In the embodiments of the present invention, terms such as first and second have been described to describe respective components, but each component should not be limited by such terms. These terms are only used to distinguish certain components from other components.

In the drawings, each component may be exaggerated for clarity. The same reference numerals denote the same elements throughout the specification.

In producing the grain-oriented electrical steel sheet micronized products on-line of acceleration and shifting, there is a problem that the magnetic flux density deteriorates and the iron loss improvement rate is low after magnetic domain micronized. The vibration of the steel sheet was considered to be due to the uneven energy of the laser. As a result, the present inventors have conducted a study for uniformizing the laser induction energy in the irradiated portion irradiated with the laser. As a result, a support roll is installed on the lower side of the steel plate opposite to the laser irradiated portion to which the laser beam is irradiated. By applying an appropriate level of tension to the steel sheet to minimize the vibration in the thickness direction of the steel sheet in the laser irradiation part, it is possible to uniformize the laser incoming energy, thereby improving the iron loss improvement rate to 10% or more without deteriorating magnetic flux density. It was investigated.

1 is a schematic diagram of a magnetizing device of a grain-oriented electrical steel sheet according to an embodiment of the present invention, Figure 2 is a schematic view showing a support constituting a device for magnetizing a grain-oriented electrical steel sheet according to an embodiment of the present invention.

In accordance with an embodiment of the present invention, a device for minimizing magnetic domains of a grain-oriented electrical steel sheet may include a laser generator 10 generating a laser beam and a direction-oriented electrical steel sheet by changing a direction of a laser beam generated from the laser generator 10. The optical means 20 to be irradiated to the surface of the 50, and the support control 30 to tension the directional electrical steel sheet to which the laser beam is irradiated by the optical means 20.

The laser beam emitted from the laser generating unit 10 is switched by the optical means 20 and irradiated onto the surface of the oriented electrical steel sheet 50, thereby miniaturizing the magnetic domain of the oriented electrical steel sheet.

The support trolley 30 is configured to contact the opposite surface of the laser irradiation part to which the laser beam a of the oriented electrical steel sheet is irradiated to give tension to the electrical steel sheet. In the embodiment of the present invention, the support trolley 30 is composed of two pieces. An absorber 40 is installed between the support trolleys 30 so as to prevent the equipment from being damaged by the laser beam outside the width of the steel sheet. The support trolley 30 prevents the shaking of the steel sheet by applying a tension of 0.1-20 kgf / mm ² to the grain-oriented electrical steel sheet, and makes the inlet energy of the laser uniform in the width direction of the steel sheet. When the tension of the steel sheet by the support roll 30 in 0.1kgf / mm ² under the conditions it is difficult to obtain an effect of equalizing the incoming laser energy, the tension of the steel sheet by the support roll 30 exceeds 20kgf / mm ² of steel sheet Since the problem of breaking and deformation occurs, it is preferable to adjust the tension of the steel sheet by the support trolley 30 to 0.1-20 kgf / mm ² .

3 is a front view showing a support control and a driving unit constituting the micronizing device of the grain-oriented electrical steel sheet according to an embodiment of the present invention. As shown, the magnetic domain micronization device according to an embodiment of the present invention includes a drive unit 60 to adjust the tension by lifting or lowering the bearing block 61 for supporting the support trolley 30 to be rotatable. Can be.

Rotating shafts 31 protrude from both side ends of the support trolley 30, and the rotating shafts 31 are rotatably supported by bearing blocks 61 fixed to the support frame 62. The bearing block 61 is connected to the drive shaft 64 interlocked with the motor 63 to be moved up or down along the LM guide formed on one side of the support frame 62 by the operation of the motor 63. The amount of rotation of the motor 63 is detected by the encoder 65 to adjust the raising and lowering height of the bearing block 61. The motor 63 may be configured as a step motor capable of precise control. Both ends of the absorber 40 are fixed to the support frame 62 and are installed between the two support pads 30 along the direction in which the laser is irradiated.

The laser generator 10 may be used without any particular limitation as long as it can generate a laser beam, such as a continuous wave CO ₂ laser, a pulse CO ₂ laser, a solid YAG or a fiber laser. The waveform of the laser beam emitted from the generator 10 is also not particularly limited. The output intensity of the laser is adjusted to an appropriate range in which the iron loss improvement rate is good but the coating layer on the surface of the steel sheet does not evaporate.

The continuous wave CO ₂ laser has a low maintenance cost and has an advantage of preventing damage to the insulating coating layer, and thus can be preferably used. Conventionally, when a continuous wave CO ₂ laser is applied to a high speed on-line of acceleration and shift, it is difficult to secure uniformity of the laser beam irradiated onto the surface of the steel sheet due to the shaking of the steel sheet during laser irradiation. By applying tension to the steel plate surface on the opposite side of the laser irradiation part to prevent the steel plate from shaking even at high speed on-line of acceleration and shifting, even when the continuous wave CO ₂ laser is irradiated to the steel plate to refine the on-line magnetic domain. The uniformity of the beam is secured to maximize the self-fineness effect.

In the embodiment shown in FIG. 1, the optical means 20 includes a beam-shaped mirror 21 and a beam-shaped mirror 21 which change directions while changing the shape of the laser beam emitted from the laser generator 10. A reflection mirror 22 for changing the direction by reflecting the laser beam whose shape has been changed by the polygon, a polygon mirror 23, and a polygon mirror 23 adapted to reflect the laser beam reflected by the reflection mirror 22 while rotating at a predetermined speed. It is composed of a scanning mirror 24 for receiving the laser beam reflected by the) and incident on the surface of the directional electrical steel sheet.

The beam-shaped mirror 21 may be composed of a curved toroidal mirror, a cylindrical mirror, or other mirror that changes the shape of the laser beam.

In the embodiment shown in FIG. 1, the beam shaped mirror 21 is provided with two of the first beam shaped mirror 21a and the second beam shaped mirror 21b.

The present invention is configured to automatically change the beam shape mirror to have a shape of a laser beam suitable for magnetic domain miniaturization selectively in accordance with the thickness change of the grain-oriented electrical steel sheet in order to fine-tune the grain-oriented electrical steel sheet on-line (On-line) To this end, a mirror adjustment unit 25 for selecting one of the first beam shape mirror 21a and the second beam shape mirror 21b is provided.

The mirror adjusting unit 25 is composed of a drive motor 26, a moving frame 27 connected to the drive shaft of the drive motor 26, the predetermined position on the moving frame 27 and the first beam-shaped mirror 21a and The second beam mirror 21b is fixed.

Therefore, when the thickness of the grain-oriented electrical steel sheet is changed in the course of minimizing on-line, the driving motor 26 is driven according to the changed thickness, and thus the position of the moving frame 27 is precisely moved to obtain an appropriate laser beam. Is converted to the corresponding beam shape mirror needed to change shape. Therefore, a suitable one among the plurality of beam shaping mirrors is automatically selected according to the thickness of the oriented electrical steel sheet, so that it is not necessary to stop the magnetization refinement for the replacement of the beam shape mirror, and the magnetization can be made on-line.

In miniaturizing the thick grain-oriented electrical steel sheet having a thickness of more than 0.27 mm, the interval between the irradiation lines (b) formed on the surface of the steel sheet by the laser beam is 4-12 mm in the rolling direction, and 400 mm or more in the steel sheet width direction. It is preferable to form an irradiation line. If the spacing between the radiation lines is less than 4mm, there is a problem that the magnetic flux density and iron loss characteristics are inferior due to the heat effect by the laser. If the spacing between the radiation lines is larger than 12mm, the fine particle diameter may be larger than the secondary recrystallized grain diameter. Almost never appear. The radiation spacing can be adjusted by varying the rotational speed of the polygon mirror.

Figure 4 is a schematic diagram showing the shape of the laser beam irradiated on the surface of the steel sheet by the method of magnetizing the grain-oriented electrical steel sheet according to an embodiment of the present invention.

The width W of the laser beam can be adjusted to 0.10 to 0.20 mm by the beam-shaped mirror, and the length L of the laser beam can be adjusted to 5 to 15 mm. The shape of the laser beam irradiated onto the steel sheet may have an oval shape, and the laser beam may be irradiated in the long axis direction of the ellipse. This is to improve the laser irradiation speed to cope with the fast line speed of the steel sheet.

In order to maximize the tensile stress in the perpendicular direction (rolling direction) of the laser irradiation line, when the width of the laser irradiation beam is W, 0.1-25 kgf / mm ² is applied to the area of 0.2 × W or more on the surface of the steel sheet by irradiation of the laser beam. Apply tensile stress.

In addition, when the thickness of the steel sheet is t, it is preferable to apply a compressive stress of 0.1 to 35 kgf / mm ² to a region of t × 0.1 or more in the thickness direction of the steel sheet, because the reason is that This is because the 180 ° domain can be miniaturized because the tensile stress can be maximized.

In FIG. 1, it is shown that one laser generating unit 10 and optical means 20 perform magnetic domain miniaturization over the entire width of the steel sheet. It can also be comprised with the several laser generation part 10 and the optical means 20. FIG.

As described above, the present invention provides a finer domain effect by applying a tension of 0.1 to 20kgf / mm ² to the steel sheet by moving a support roll to contact the opposite side of the laser irradiation section of the steel sheet when irradiating a laser beam for miniaturizing the domain. Can be maximized. In addition, by arranging the beam-shaped mirror required by the automatic adjustment according to the thickness of the steel sheet, the magnetic domain can be miniaturized in a high speed on-line of variable and variable speed, and the magnetic domain can be miniaturized even when the feed speed of the steel sheet is 300mpm or more. . Therefore, even in the case where the thickness of the steel sheet is changed, it is possible to continuously refine the magnetic domain without having to interrupt the process for replacing the beam-shaped mirror.

Hereinafter, the present invention will be described in more detail with reference to Examples.

The laser beam emitted from the continuous wave CO ₂ laser was irradiated onto the surface of the thick oriented electrical steel sheet having a thickness of 0.30 mm to perform magnetic domain micronization. In some cases, the support trol was brought into contact with the surface opposite the laser irradiation part to give tension to the steel sheet. Irradiation line spacing by magnetic domain miniaturization was 5.3 mm. Iron loss, magnetic flux density, and laser irradiation stress before and after magnetic domain micronization were measured for each, and are shown in Table 1 below. The magnetic energy of the laser beam was controlled within 4500 ~ 7500mJ range.

Laser irradiation conditions Iron loss (W17 / 50; W / Kg) /
Magnetic flux density (B8; Tesla) Iron loss
Improvement rate
(%) Laser irradiation stress
(Kgf / mm ² ) On-line
apply
Remarks tension Beam shape
(Width × length, mm) Before Fine-Graining After miniaturization Rolling direction Thickness direction is it 0.15 × 25 0.93 / 1.91 0.83 / 1.91 10.7 25 -23 possible Honor is it 0.15 × 10 0.94 / 1.92 0.84 / 1.92 10.6 13 -16 possible Honor Unauthorized 0.15 × 6.0 0.96 / 1.92 0.86 / 1.90 6.2 4 -6 Impossible Comparative example Unauthorized 0.15 × 10 0.95 / 1.92 0.82 / 1.89 6.2 0.1 -4 Impossible Comparative example

In the present invention in which tension was applied by the support trolley, the magnetic flux density was not deteriorated after magnetic domain micronization, and the iron loss improvement rate was more than 10%. On the other hand, in the comparative example without tension by the support trolley, the magnetic flux density was deteriorated after magnetic domain micronization, and the iron loss improvement rate was lower than 10%.

The laser beam emitted from the continuous wave CO ₂ laser was irradiated onto the surface of the thick oriented electrical steel sheet having a thickness of 0.30 mm to perform magnetic domain micronization. At this time, the support pad was placed on the opposite side of the laser irradiator to impart a tension of 13 Kgf / mm ² to the steel sheet. Iron loss, magnetic flux density, and laser irradiation stress before and after magnetic domain micronization were measured for each, and are shown in Table 2 below.

division Survey ship
Spacing (mm) Laser insertion
Energy (mJ) Laser irradiation stress
(Kgf / mm ² ) Iron loss (W17 / 50) / magnetic flux density (B8) Iron loss
Improvement rate
(%) Remarks Rolling direction Thickness direction Jaguar Fine Artization After miniaturization One 2 6000 3 -10 0.93 / 1.92 0.95 / 1.90 2.1 Comparative example 2 3 6000 4 -7 0.94 / 1.91 0.95 / 1.90 1.1 Comparative example 3 4 7000 22 -23 0.94 / 1.92 0.84 / 1.92 10.6 Honor 4 6 4000 5 -6 0.94 / 1.92 0.91 / 1.91 3.2 Comparative example 5 6 6000 16 -18 0.93 / 1.92 0.86 / 1.92 7.5 Honor 6 8 5000 14 -16 0.94 / 1.91 0.88 / 1.91 6.4 Honor 7 8 8000 6 -7 0.95 / 1.91 0.92 / 1.91 3.2 Comparative example 8 10 5000 8 -10 0.94 / 1.92 0.89 / 1.92 5.3 Honor 9 12 6000 7 -8 0.93 / 1.91 0.89 / 1.91 4.3 Honor 10 15 6000 One -1.5 0.95 / 1.92 0.95 / 1.91 0.0 Comparative example

From the results in Table 2, when the thickness of the grain-oriented electrical steel sheet is reduced, the irradiation distance is set to 4 to 12 mm and the laser irradiation energy is controlled to 4500 to 7500 mJ, and the laser irradiation stress in the rolling direction is 0.1 to 25 Kgf / mm ² . It is confirmed that the laser irradiation stress in the thickness direction is 0.1 to 35 Kgf / mm ² so that the magnetic flux density does not deteriorate and a high iron loss improvement rate of 10% or more is secured.

DESCRIPTION OF SYMBOLS 10 Laser generation part 20 Optical means 21 Beam shape mirror
22: reflection mirror 23: polygon mirror 24: scanning mirror
25: mirror adjusting unit 26: drive motor 27: moving frame
30: support trolley 31: rotation axis 40: absorber
60: drive unit 61: bearing block 62: support frame
63: motor 64: drive shaft 65: encoder

Claims (13)

In the magnetic domain micronizing device of a grain-oriented electrical steel sheet having a thickness of more than 0.27mm,
A laser generator for generating a laser beam;
Optical means for irradiating a predetermined surface of the directional electrical steel sheet by changing a direction of a laser beam generated from the laser generator;
A plurality of support pads disposed opposite the surface and in contact with the oriented electrical steel sheet to which the laser beam is irradiated by the optical means, and to tension the surface; And
And a drive unit configured to adjust a tension by elevating a bearing block rotatably supporting any one of the support pads. The method according to claim 1,
The laser beam is a continuous wave CO2 laser, the magnetic domain device of the grain-oriented electrical steel sheet. The method according to claim 1 or 2,
The support trolley micronized device of the grain-oriented electrical steel sheet for applying a tension of 0.1 ~ 20kgf / mm ² to the grain-oriented electrical steel sheet. delete In the magnetic domain micronizing device of a grain-oriented electrical steel sheet having a thickness of more than 0.27mm,
A laser generator for generating a laser beam;
Optical means for irradiating the surface of the directional electrical steel sheet by changing the direction of the laser beam generated from the laser generator; And
It includes a support to contact the directional electrical steel sheet is irradiated with the laser beam by the optical means to give a tension,
The optical means,
A plurality of beam shape mirrors for changing the shape of the laser beam generated from the laser generation unit; And a mirror adjusting unit for automatically adjusting any one of a plurality of beam-shaped mirrors according to the thickness of the directional electrical steel sheet. In the method of refining the magnetic domain of a grain-oriented electrical steel sheet having a thickness of more than 0.27mm,
The bearing block irradiates a laser beam to a predetermined surface of the oriented electrical steel sheet, and supports the support blocks on the opposite side of the surface to rotatably support any one of the support throttles in contact with the oriented electrical steel sheet. A method for minimizing magnetic domains of a grain-oriented electrical steel sheet by lifting and applying tension to the surface. The method of claim 6,
And the laser beam is a continuous wave CO2 laser. The method according to claim 6 or 7,
Magnetic domain micronizing method of the grain-oriented electrical steel sheet, applying a tension of 0.1 ~ 20kgf / mm ^{2 to} the grain-oriented electrical steel sheet. The method according to claim 6 or 7,
The method of micro-magnetizing the grain-oriented electrical steel sheet such that the tensile stress is 0.1 to 25 kgf / mm ² in a region of 0.2 times or more of the width of the laser beam in the longitudinal direction of the grain-oriented electrical steel sheet. The method according to claim 6 or 7,
A method for miniaturizing magnetic domains of a grain-oriented electrical steel sheet such that the compressive stress is 0.1 to 35 kgf / mm ² in a region at least 0.1 times the thickness of the grain-oriented electrical steel sheet in the thickness direction under the irradiation line by a laser beam. In the magnetic domain micronizing method of a grain-oriented electrical steel sheet having a thickness of more than 0.27mm to irradiate the surface with a laser beam to refine the magnetic domain,
The support trolley contacts the oriented electrical steel sheet to apply tension to the oriented electrical steel sheet to which the laser beam is irradiated.
The method for fine-magnetizing the grain-oriented electrical steel sheet according to claim 1, wherein the one of the plurality of beam-shaped mirrors is automatically adjusted according to the thickness of the grain-oriented electrical steel sheet. The method according to claim 6 or 7,
The method of micro-magnetizing the grain-oriented electrical steel sheet according to claim 1, wherein the distance between the irradiation lines formed on the surface of the steel sheet by the laser beam is 4.0-12.0 mm, and the laser beam is irradiated on the surface of the steel sheet so that the inlet energy of the laser is 4500-7500 mJ. The method according to claim 6 or 7,
Compared to before magnetization, there is no deterioration in magnetic flux density, and the iron loss improvement rate is 10% or more.

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