[Document Type] SPECIFICATION
[Title of the Invention] APPARATUS FOR MANUFACTURING GRAINORIENTED
ELECTRICAL STEEL SHEET AND METHOD OF
MANUFACTURING GRAIN-ORIENTED ELECTRICAL STEEL SHEET
[Technical Field]
[0001]
The present invention relates to an apparatus for manufacturing a grainoriented
electrical steel sheet in which a magnetic domain is controlled by irradiation
of a laser beam and a method of manufacturing a grain-oriented electrical steel sheet.
[Background Art]
[0002]
The above-mentioned grain-oriented electrical steel sheet is used as a material
included in the iron core of an electrical device such as a transformer or a rotating
device. In the grain-oriented electrical steel sheet, a reduction in energy loss (iron
loss) during magnetization is required. Iron loss is classified into eddy-current loss
and hysteresis loss. Furthermore, eddy-current loss is classified into classical eddycurrent
loss and anomalous eddy-current loss.
[0003]
Here, in order to reduce the classical eddy-current loss, a grain-oriented
electrical steel sheet having an insulating film formed on the sheet surface and having a
small sheet thickness has been provided. As the grain-oriented electrical steel sheet
having the insulating film formed on thereof, for example, as described in Patent
Document 1, a grain-oriented electrical steel sheet in which a glass film is formed on
the surface of the steel sheet and an insulating film is further formed on the glass film,
is suggested. , **
- 1 -
[0004]
In addition, in order to suppress the anomalous eddy-current loss, as described,
for example, in Patent Document 2, a magnetic domain control method, in which a
laser beam is converged and irradiates and scans a magnetic steel sheet in a
substantially width direction from above an insulating film to form laser irradiation
• lines that extend in the width direction on the surface of the steel sheet such that a
region which periodically has residual strains in a rolling direction is provided to
divide magnetic domains, is suggested.
[0005]
In a case where magnetic domain control is performed by the above-described
laser irradiation, there is a need to control an interval PL between the laser irradiation
lines in the rolling direction to be constant by repeatedly scanning the transferred steel
sheet in the width direction with the laser beams using a laser beam irradiation device.
Here, there is a limitation on the scanning speed of the laser beam by the laser beam
irradiation device, and thus in a case where the steel sheet having a large width is
transferred at a high speed, there is a case that the interval PL between the laser
irradiation Imes in the rolling direction cannot be formed at a predetermined interval.
[0006]
Therefore, for example, in Patent Document 3, a method of forming laser
irradiation lines divided in the width direction of the steel sheet by a plurality of laser
beam irradiation devices arranged along the width direction of the steel sheet is
disclosed.
[0007]
However, in a case where the laser irradiation lines are formed to be divided
in the width direction, it is important that iron loss of the steel sheet and
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magnetostrictive properties associated with transformer noise, in the entire width
direction, are constant. Specifically, at a boundary portion between the divided laser
irradiation lines, the irradiation state of the laser beam is different from that of the
other portions, and thus iron loss and magnetostrictive properties may be deteriorated.
[0008]
From these circumstances, an apparatus for manufacturing a grain-oriented
electrical steel sheet capable of stabilizing iron loss and magnetostrictive properties in
the entire width direction of a steel sheet even in a case where the magnetic domain
control is performed by forming laser irradiation lines while the steel sheet having a
large width is transferred at a high speed, and a method of manufacturing a grainoriented
electrical steel sheet have been required.
[Prior Art Document]
[Patent Document]
[0009]
[Patent Document 1] Japanese Unexamined Patent Application, First
Publication No.2007-119821
[Patent Document 2] Published Japanese Translation No.2003-500541 of the
PCT International Publication
[Patent Document 3] Japanese Unexamined Patent Application, First
Publication No. S63-083227
[Disclosure of the Invention]
[Means for Solving the Problems]
[0010]
According to the present invention, an apparatus for manufacturing a grainoriented
electrical steel sheet in which a magnetic domain is controlled by irradiation
of a laser beam, includes: a plurality of laser beam irradiation devices which are
arranged in a transfer direction of a steel sheet; and a width-direction movement
mechanism which moves the laser beam irradiation device in a width direction of the
steel sheet. The width-direction movement mechanism is able to move the laser beam
irradiation device over the entire width of the steel sheet.
[0011]
In this case, by the plurality of laser beam irradiation devices which are
arranged in the transfer direction of the steel sheet, a plurality of laser irradiation lines
divided in the width direction can be formed on the surface of the steel sheet.
Accordingly, the scanning length of one of the laser beam irradiation devices can be set
to be short, and thus even in a case where the steel sheet having a large width is
transferred at a high speed, the laser irradiation lines can be formed at a predetermined
interval PL in a rolling direction.
In addition, each of the laser beam irradiation devices can scan the steel sheet
in the width direction with the laser beam at an arbitrary position in the width direction
of the steel sheet, and thus an overlap width of laser irradiation lines adjacent to each
other in the width-direction can be adjusted. Accordingly, magnetic properties or
magnetostrictive properties in the entire width direction of the steel sheet can be
stabilized.
[0012]
Here, at least N+l laser beam irradiation devices may be included, and
irradiation of laser beams may be performed on the entire width of the steel sheet by
the N laser beam irradiation devices.
[0013]
In this case, one or more of the laser beam irradiation devices are ensured as
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t
standby devices. Even the standby devices can be moved by the width-direction
movement mechanism over the entire width of the steel sheet, and thus the standby
laser beam irradiation devices can be immediately used by replacing the laser beam
irradiation device having problems.
[0014]
According to the present invention, a method of manufacturing a grainoriented
electrical steel sheet in which a magnetic domain is controlled by irradiation
of a laser beam, includes: a laser irradiation process of separately scanning a
transferred steel sheet in the width direction with laser beams to form a plurality of
laser irradiation lines separated in the width direction on the surface of the steel sheet.
In the laser irradiation process, an overlap width of the laser irradiation lines adjacent
to each other in the width direction is adjusted.
[0015]
In this case, in the laser irradiation process, by adjusting the overlap width of
the laser irradiation lines adjacent to each other in the width direction, magnetic
properties and magnetostrictiye properties in the entire width direction of the steel
sheet can berstabilized.
For example, by setting the overlap width of the laser irradiation lines
adjacent to each other in the width direction to be -5 mm or greater and 20 mm or less,
an increase in the iron loss can be suppressed.
Otherwise, by setting the overlap width of the laser irradiation lines adjacent
to each other in the width direction to be 10 mm or less, an increase in the
magnetostriction rate level (LVA) as an index of magnetostriction can be suppressed.
In addition, a case of a minus overlap width represents the separation of the laser
irradiation lines.
- 5 -
t
[Advantage of the Invention]
[0016]
According to the present invention, it is possible to provide an apparatus for
manufacturing a grain-oriented electrical steel sheet and a method of manufacturing a
grain-oriented electrical steel sheet, which are capable of stabilizing the magnetic
properties and magnetostrictive properties in the entire width direction of the steel
sheet even in a case where magnetic domain control is performed by forming the laser
irradiation lines while the steel sheet having a large width is transferred at a high
speed,.
[Brief Description of the Drawing]
[0017]
FIG. 1 is an explanatory top view illustrating an apparatus for manufacturing a
grain-oriented electrical steel sheet in an embodiment of the present invention.
FIG. 2 is an explanatory side view of the apparatus for manufacturing a grainoriented
electrical steel sheet illustrated in FIG. 1.
FIG 3 is an explanatory schematic view of a laser beam irradiation device.
FIG/4 is'an explanatory view illustrating an example of a grain-oriented
electrical steel sheet manufactured by the apparatus for manufacturing a grain-oriented
electrical steel sheet in the embodiment of the present invention.
FIG. 5 is an enlarged explanatory view of laser irradiation lines in FIG. 4.
FIG. 6 is an explanatory view illustrating another example of the grainoriented
electrical steel sheet manufactured by the apparatus for manufacturing a grainoriented
electrical steel sheet in the embodiment of the present invention.
FIG 7 is an enlarged explanatory view of laser irradiation lines in FIG. 6.
FIG. 8 is a graph showing results of Example 1.
- 6 -
FIG. 9 is a graph showing results of Example 2.
[Embodiments of the Invention]
[0018]
In addition, an apparatus for manufacturing a grain-oriented electrical steel
sheet in this embodiment will be described using FIGS. 1 to 3.
The apparatus 10 for manufacturing a grain-oriented electrical steel sheet
irradiates a steel sheet 31 which is transferred in a rolling direction with a laser beam to
perform magnetic domain control of the steel sheet 31.
[0019]
As shown in FIG. 1, the apparatus 10 for manufacturing a grain-oriented
electrical steel sheet in this embodiment includes a laser device 12 which emits a laser
beam, a plurality of laser beam irradiation devices 20 which are arranged in a transfer
direction of the steel sheet 10, and a linear motion device 15 which moves the laser
beam irradiation devices 20 in a width direction of the steel sheet 31.
[0020]
Here, in this embodiment, as shown in FIGS. 1 and 2, six laser beam
irradiation devices 20 are arranged. Among these, five laser beam irradiation devices
20 are configured to irradiate the entire width of the steel sheet 31 with laser beams,
and one laser beam irradiation device 20a is on standby at a position that deviates from
the upper side of the steel sheet 31. In addition, as shown in FIG. 2, the laser beam
irradiation devices 20 are respectively arranged above a plurality of support rolls 11
provided in the transfer direction.
[0021]
The laser device 12 emits a laser beam which can be transmitted through fiber.
As the laser beam which can be transmitted through fiber, a YAG laser (a wavelength
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9
of 1.06 um), a fiber laser (a wavelength of 1.07 to 1.08 jam), and the like may be
applied.
The laser beam emitted by the laser device 12 is transmitted to the
corresponding laser beam irradiation device 20 via a transmission fiber 13.
[0022]
As shown in FIG 3, the laser beam irradiation device 20 includes a collimator
21, a polyhedral rotating polygon mirror 22, and an fB lens 23.
The collimator 21 adjusts the diameter of a laser beam LB which is output
from the transmission fiber 13. In addition, the rotating polygon mirror 22 deflects
the laser beam LB and scans the steel sheet 31 at a high speed in the width direction of
the steel sheet 31. The fB lens 23 converges the laser beam LB scanned by the
rotating polygon mirror 22.
[0023]
Here, by adjusting the rotational speed of the rotating polygon mirror 22, the
scanning speed of the laser beam LB on the steel sheet 31 can be adjusted.
In addition, the laser beam irradiation device 20 includes a focusing
mechanism .(not illustrated) which simultaneously moves the rotating polygon mirror
22 and the fB lens 23 up and down, and a range finder (not illustrated) which measures
the distance between the steel sheet 31 and the fB lens 23. The distance between the
fB lens 23 and the steel sheet 31 can be adjusted by the focusing mechanism.
[0024]
The linear motion device 15 includes a guide rail 16 which extends in the
width direction of the steel sheet 31. As shown in FIG. 1, the guide rail 16 is set to be
longer than the width of the steel sheet 31 transferred, and extends to protrude from
both ends of the steel sheet 31 in the width direction.
- 8 -
It
The linear motion device 15 includes driving measures (not illustrated) for
driving the laser beam irradiation device 20 along the guide rail 16. As the driving
measures, for example, a combination of a ball screw and a rotary motor or a linear
motor may be employed.
[0025]
By the linear motion device 15, the corresponding laser beam irradiation
device 20 can be moved to an arbitrary position in the width direction of the steel sheet
31.
In addition, in the linear motion device 15, a position sensor (not illustrated)
which specifies the position of the corresponding laser beam irradiation device 20 is
provided.
[0026]
Next, a method of manufacturing a grain-oriented electrical steel sheet using
the apparatus 10 for manufacturing a grain-oriented electrical steel sheet in this
embodiment will be described.
First, width data of the steel sheet 31 irradiated with the laser beam LB is
obtained. From the width data, the number of the laser beam irradiation devices 20
used is determined. In this embodiment, as shown in FIG. 1, the five laser beam
irradiation devices 20 are used.
[0027]
In addition, the position of the laser beam irradiation device 20 in the width
direction is determined, and the laser beam irradiation device 20 is moved to the
predetermined position by using the linear motion device 15. In addition, the laser
beam irradiation device 20a which is not used is moved to a retreat position.
Furthermore, the, scanning length of the laser beam LB in the laser beam
- 9 -
irradiation device 20 is determined. The scanning width of the laser beam LB is a
value obtained by multiplying the angle of reflection of the polygon mirror, namely,
the number of polygon surface, by the focal length of the fB lens. At this time,
according to the positions of the laser beam irradiation devices 20 in the width
direction, an overlap width d of laser irradiation lines 32 adjacent to each other in the
width direction is adjusted.
Otherwise, in order to change the scanning width of the laser beam LB, the
scanning width on the steel sheet may be changed by shielding an end of the scanning
beam with a shield plate provided between the ft) lens and the steel sheet. Otherwise,
the polygon mirror and the fB lens may be changed.
Otherwise, the scanning width may be changed by changing a mirror
reflection angle using a galvano motor which causes a mirror to oscillate at an arbitrary
angle instead of the polygon mirror.
In addition, a series of setting operations may be configured to be
automatically set by a calculator using a program.
[0028]
Next;-the'laser beam LB is emitted by the laser device 12. The laser beam
LB is transmitted to the corresponding laser beam irradiation device 20 via the
transmission fiber 13.
In the laser beam irradiation device 20, the laser beam LB scans the steel
sheet 31 via one surface of the rotating polygon mirror 22 which rotates. Accordingly,
the laser irradiation line 32 having a predetermined length is formed on the surface of
the steel sheet 31. At this time, the laser irradiation line may be a visible line which is
formed by evaporating a glass film or an insulating film on the surface or may be an
invisible line that is not subjected to evaporation, if a strain is imparted to efficiently
- 10 -
achieve magnetic domain control.
An interval PL between the laser irradiation lines 32 adjacent to each other in
the transfer direction can be changed by adjusting the transfer speed of the steel sheet
31 and the rotational speed of the rotating polygon mirror 22.
In addition, the laser irradiation line 32 can also be formed in a groove shape
by increasing the output of the laser beam LB, reducing the converged beam diameter,
or reducing the scanning speed.
[0029]
Next, an example of the grain-oriented electrical steel sheet manufactured by
using the apparatus 10 for manufacturing a grain-oriented electrical steel sheet in this
embodiment will be described using FIGS. 4 and 5.
The grain-oriented electrical steel sheet includes the steel sheet, the glass film
formed on the surface of the steel sheet, and the insulating film formed on the glass
film. In addition, the surface of the grain-oriented electrical steel sheet is irradiated
and scanned with the laser beam LB from above the insulating film such that the laser
irradiation line 32 that extends to be substantially perpendicular to the rolling direction
is formed as^S'hown in FIG 4.
[0030]
The laser irradiation lines 32 are formed at a predetermined period in the
rolling direction, and in a region where magnetization points in the rolling direction
between the two laser irradiation lines 32 and 32, a magnetic domain width in the
direction substantially perpendicular to the rolling direction is subdivided.
The grain-oriented electrical steel sheet illustrated in FIGS. 4 and 5 is
exemplified so that the laser irradiation lines 32 are divided in the width direction and
the laser irradiation lines 32 and 32 adjacent to each other in the width direction
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overlap by a width d.
[0031]
In addition, another example of the grain-oriented electrical steel sheet
manufactured by using the apparatus for manufacturing a grain-oriented electrical steel
sheet in this embodiment will be described using FIGS. 6 and 7.
The grain-oriented electrical steel sheet is exemplified so that the laser
irradiation lines 32 are divided in the width direction and the laser irradiation lines 32
and 32 adjacent to each other in the width direction are separated by a width d. In
addition, in the case where the laser irradiation lines 32 and 32 are separated from each
other, the overlap width d is set to be minus.
[0032]
In this manner, in the apparatus 10 for manufacturing a grain-oriented
electrical steel sheet in this embodiment, as described above, the overlap width d of the
laser irradiation lines 32 and 32 adjacent to each other in the width direction can be
adjusted by the position of the corresponding laser beam irradiation device 20 in the
width direction and the scanning length of the laser beam LB in the corresponding
laser beam -iffadiation device 20.
[0033]
In the apparatus 10 for manufacturing a grain-oriented electrical steel sheet in
this embodiment configured as described above, since the plurality of (in this
embodiment, six) laser beam irradiation devices 20 which are arranged in the transfer
direction of the steel sheet 31 and the linear motion devices 15 which moves the
respective laser beam irradiation devices 20 in the width direction of the steel sheet 31
are provided, the plurality of laser irradiation lines 32 which are divided in the width
direction can be formed on the surface of the steel sheet 31. Accordingly, the
- 12 -
scanning length of the laser beam LB in the one laser beam irradiation device 20 can
be set to be short, and thus even in a case where the steel sheet 31 having a large width
is transferred at a high speed, the laser irradiation lines 32 can be formed at the
predetermined interval PL in the rolling direction.
[0034]
In addition, since the overlap width d of the laser irradiation lines 32 and 32
adjacent to each other in the width direction can be adjusted by the position of the
corresponding laser beam irradiation device 20 in the width direction and the scanning
length of the laser beam LB in the corresponding laser beam irradiation device 20, iron
loss and magnetostrictive properties of the steel sheet 31 in the entire width direction
can be stabilized.
[0035]
As an example, using a grain-oriented electrical steel sheet having a sheet
thickness of 0.23 mm,_iron loss value after laser irradiation were obtained when the
overlap width d is variously changed. In the grain-oriented electrical steel sheet used,
a magnetic flux density which is generated by a magnetic field of 0.8 A/m is 1.92 T.
Laser conditions include a laser power of 200 W, a beam scanning speed of 30 m/s, and
a condensed beam diameter of
Hereinafter, the results of evaluation on the relationship between the overlap
width d of the laser irradiation line formed on the steel sheet and the iron loss are
described.
As shown in FIG. 8, it is determined that when the overlap width d of the laser
irradiation litres adjacent to each other in the width direction is in the range of-5 to 20
mm, the iron loss of W17/50 can be significantly reduced.
[0042]
< Relationship Between Overlap Width d of Laser Irradiation Lines and
Magnetostriction>
Hereinafter, the results of evaluation on the relationship between the overlap
width d of the laser irradiation lines formed on the steel sheet and the magnetostriction
are described.
As shown in FIG. 9, it is confirmed that when the interval d of the laser
- 16 -
irradiation lines adjacent to each other in the width direction is 10 mm or less, an
increase in the LVA can be suppressed.
[0043]
While the embodiments of the present invention have been described above,
the present invention is not limited thereto and can be appropriately modified without
departing from the technical spirit of the present invention.
For example, in the description, the laser beam which can be transmitted
through fiber is used. However, the present invention is not limited thereto, and a
carbon dioxide laser or the like may also be used. In this case, the laser beam is
transmitted to the corresponding laser beam irradiation device by reflections of a
plurality of mirrors.
Otherwise, a structure in which both the laser device and the irradiation
device are provided in a width-direction movement mechanism so as to be moved may
also be employed.
[0044]
In addition, in the d£Scription, the laser beam irradiation device is moved in
the width difectidn by using the linear motion device. However, the present invention
is not limited thereto, and the laser beam irradiation device may be moved in the width
direction by other movement mechanisms.
[Industrial Applicability]
[0045]
According to the present invention, even in a case where laser processing is
performed while the steel sheet having a large width is transferred at a high speed, the
grain-oriented electrical steel sheet having stabilized iron loss and magnetostrictive
properties in the entire width direction of the steel sheet, the apparatus for
- 17 -
manufacturing the grain-oriented electrical steel sheet, and the method of
manufacturing the same can be provided.
[Description of Reference Numerals and Signs]
[0046]
10: METHOD OF MANUFACTURING GRAIN-ORIENTED ELECTRICAL
STEEL SHEET
15: LINEAR MOTION DEVICE (WIDTH-DIRECTION MOVEMENT
MECHANISM)
20: LASER BEAM IRRADIATION DEVICE
31: STEEL SHEET
32: LASER IRRADIATION LINE

-IP--
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[Designation of Document] CLAIMS
[Claim 1] . .'
An apparatus for manufacturing a grain-oriented electrical steel sheet in which
a magnetic domain is controlled by irradiating a laser beam, comprising:
a plurality of laser beam irradiation devices which are arranged in a transfer
direction of a steel sheet; and
a width-direction movement mechanism which moves the laser beam
irradiation devices in a width direction of the steel sheet,
wherein the width-direction movement mechanism is able to move the laser
beam irradiation devices over an entire width of the steel sheet.
[Claim 2]
The apparatus for manufacturing a grain-oriented electrical steel sheet
according to claim 1,
wherein at least N+l laser beam irradiation devices are included, and
irradiation of laser beams is performed on the entire width of the steel sheet
by the N laser beam irradiation-devices.
[Claim 3]
A method of manufacturing a grain-oriented electrical steel sheet in which a
magnetic domain is controlled by irradiating laser beams, comprising:
a laser irradiation process of separately scanning a transferred steel sheet in a
width direction with the laser beams to form a plurality of laser irradiation lines
separated in the width direction on a surface of the steel sheet,
wherein, in the laser irradiation process, an overlap width of the laser
irradiation lines adjacent to each other in the width direction is adjusted.