JP5841594B2 - Method for producing grain-oriented electrical steel sheet - Google Patents

Description

This invention relates to a manufacturing method of oriented electrical steel sheets whichever is the magnetic domain control by laser beam irradiation.

The above-mentioned grain-oriented electrical steel sheet is used as a material constituting an iron core of electrical equipment such as a transformer and a rotating machine. Such a grain-oriented electrical steel sheet is required to reduce energy loss (iron loss) when magnetized. Iron loss is classified into eddy current loss and hysteresis loss. Furthermore, eddy current loss is classified into classical eddy current loss and abnormal eddy current loss.

Here, in order to reduce the classical eddy current loss, a thin directional electrical steel sheet having an insulating film formed on the plate surface is provided. As a grain-oriented electrical steel sheet having an insulating film formed thereon, for example, as shown in Patent Document 1, a glass film is formed on the surface of the steel sheet, and an insulating film is further formed on the glass film. Yes.

  Moreover, in order to suppress abnormal eddy current loss, for example, as shown in Patent Document 2, a laser beam is focused and irradiated from above the insulating film, and scanned in the substantially width direction of the electromagnetic steel sheet to the surface of the steel sheet. A magnetic domain control method has been proposed in which a laser irradiation line extending in the width direction is formed, a region having a residual strain is periodically provided in the rolling direction, and the magnetic domains are subdivided.

  When performing the above-described magnetic domain control by laser irradiation, the laser beam scanning is repeated in the width direction of the steel sheet to be conveyed using the laser beam irradiation apparatus so that the interval PL in the rolling direction of the laser irradiation lines becomes constant. Need to control. Here, since there is a limit to the scanning speed of the laser beam by the laser beam irradiation apparatus, when conveying a wide steel plate at a high speed, the interval PL in the rolling direction of the laser irradiation line cannot be formed at a predetermined interval. There was a thing.

  Thus, for example, Patent Document 3 discloses a method of forming laser irradiation lines divided in the width direction of a steel sheet by a plurality of laser beam irradiation apparatuses arranged along the width direction of the steel sheet.

  By the way, when the laser irradiation line is divided and formed in the width direction, it is important to make the magnetostriction characteristics related to iron loss and transformer noise constant throughout the width direction of the steel sheet. More specifically, since the irradiation state of the laser beam is different from the others at the boundary portion of the divided laser irradiation lines, the iron loss and magnetostriction characteristics may be deteriorated.

  From such a situation, even when the magnetic domain control is performed by forming a laser irradiation line while conveying a wide steel plate at high speed, it is possible to stabilize the iron loss and magnetostriction characteristics in the entire width direction of the steel plate. A manufacturing apparatus for grain-oriented electrical steel sheets and a method for producing grain-oriented electrical steel sheets have been demanded.

JP 2007-119821 A Japanese translation of PCT publication No. 2003-500541 JP 63-083227 A

A method for producing a grain-oriented electrical steel sheet according to the present invention is a method for producing a grain-oriented electrical steel sheet for producing a magnetic domain-controlled grain-oriented electrical steel sheet by irradiating a laser beam. The laser beam irradiation apparatus is used to divide and scan the laser beam in the width direction of the steel plate to be conveyed, and a plurality of laser irradiation lines divided in the width direction are adjacent to the surface of the steel plate in the width direction. A laser irradiation step of forming the laser irradiation lines to be matched so that the positions in the transport direction are different, and the laser beam irradiation apparatus is configured to be capable of changing the scanning width of the laser beam in the width direction of the steel plate. In this laser irradiation step, the position in the width direction of the laser beam irradiation apparatus and the scanning width of the laser beam of the laser beam irradiation apparatus are adjacent to each other in the width direction and the position in the transport direction. Method for producing a grain-oriented electrical steel sheet, characterized in that to adjust the width direction of the overlapping width of the steel plate between different laser radiation to -5～0Mm.

In this case, in the laser irradiation step, by adjusting the overlapping width of the laser irradiation lines adjacent in the width direction, it is possible to stabilize the magnetic characteristics and the magnetostriction characteristics in the entire width direction of the steel sheet.
For example, it is possible to suppress an increase in iron loss by setting the overlapping width of the laser irradiation lines adjacent in the width direction to be −5 mm or more and 20 mm or less.
Alternatively, an increase in magnetostriction speed level (LVA), which is an index of magnetostriction, can be suppressed by setting the overlapping width of the laser irradiation lines adjacent in the width direction to 10 mm or less. In addition, when the overlap width is negative, it indicates that the laser irradiation lines are separated from each other.

According to the present invention, it is possible to stabilize the magnetic characteristics and magnetostrictive characteristics in the entire width direction of the steel sheet even when the magnetic domain control is performed by forming a laser irradiation line while conveying a wide steel sheet at a high speed. A method for producing a grain-oriented electrical steel sheet can be provided.

It is upper surface explanatory drawing which shows the manufacturing apparatus of the grain-oriented electrical steel plate which is embodiment of this invention. It is side explanatory drawing of the manufacturing apparatus of the grain-oriented electrical steel plate shown in FIG. It is a schematic explanatory drawing of a laser beam irradiation apparatus. It is explanatory drawing which shows an example of the grain-oriented electrical steel plate manufactured with the manufacturing apparatus of the grain-oriented electrical steel plate which is embodiment of this invention. FIG. 5 is an enlarged explanatory view of a laser irradiation line in FIG. 4. It is explanatory drawing which shows the other example of the grain-oriented electrical steel plate manufactured with the manufacturing apparatus of the grain-oriented electrical steel plate which is embodiment of this invention. FIG. 7 is an enlarged explanatory view of a laser irradiation line in FIG. 6. 3 is a graph showing the results of Example 1. 10 is a graph showing the results of Example 2.

First, the manufacturing apparatus of the grain-oriented electrical steel sheet which is this embodiment is demonstrated using FIGS. 1-3.
The grain-oriented electrical steel sheet manufacturing apparatus 10 irradiates a laser beam to a steel sheet 31 transported in the rolling direction to perform magnetic domain control of the steel sheet 31.

  As shown in FIG. 1, the grain-oriented electrical steel sheet manufacturing apparatus 10 according to the present embodiment includes a laser apparatus 12 that oscillates a laser beam, a plurality of laser beam irradiation apparatuses 20 that are arranged in the conveying direction of the steel sheet 10, and And a linear motion device 15 that moves the laser beam irradiation device 20 in the width direction of the steel plate 31.

  Here, in this embodiment, as shown in FIGS. 1 and 2, six laser beam irradiation apparatuses 20 are provided. Of these, five laser beam irradiation devices 20 are configured to irradiate the entire width of the steel plate 31 with a laser beam, and one laser beam irradiation device 20 a is on standby at a position off the steel plate 31. Yes. In addition, as shown in FIG. 2, each laser beam irradiation apparatus 20 is each arrange | positioned above the support roll 11 provided with two or more by the conveyance direction.

The laser device 12 oscillates a laser beam that can be transmitted through a fiber. As a laser beam that can be transmitted through a fiber, a YAG laser (wavelength 1.06 μm), a fiber laser (wavelength 1.07 to 1.08 μm), or the like can be applied.
The laser beam oscillated by the laser device 12 is transmitted to each laser beam irradiation device 20 through the transmission fiber 13.

As shown in FIG. 3, the laser beam irradiation apparatus 20 includes a collimator 21, a polyhedral rotating polygon mirror 22, and an fθ lens 23.
The collimator 21 adjusts the diameter of the laser beam LB output from the transmission fiber 13. The rotating polygon mirror 22 deflects the laser beam LB to scan the steel plate 31 in the width direction of the steel plate 31 at high speed. The fθ lens 23 condenses the laser beam LB scanned by the rotating polygon mirror 22.

Here, the scanning speed of the laser beam LB on the steel plate 31 can be adjusted by adjusting the rotational speed of the rotating polygon mirror 22.
The laser beam irradiation apparatus 20 includes a focus mechanism (not shown) that moves the rotating polygon mirror 22 and the fθ lens 23 simultaneously and a distance meter (not shown) that measures the distance between the steel plate 31 and the fθ lens 23. And. The distance between the fθ lens 23 and the steel plate 31 can be adjusted by this focus mechanism.

The linear motion device 15 includes a guide rail 16 that extends in the width direction of the steel plate 31. As shown in FIG. 1, the guide rail 16 is set longer than the width of the steel plate 31 to be conveyed and extends so as to protrude from both ends of the steel plate 31 in the width direction.
The linear motion device 15 includes drive means (not shown) for driving the laser beam irradiation device 20 along the guide rail 16. Examples of the driving means include a combination of a ball screw and a rotary motor, a linear motor, and the like.

With this linear motion device 15, each laser beam irradiation device 20 can be moved to an arbitrary position in the width direction of the steel plate 31.
Further, the linear motion device 15 is provided with a position sensor (not shown) for specifying the position of each laser beam irradiation device 20.

Next, a method for producing a grain-oriented electrical steel sheet using the grain-oriented electrical steel sheet production apparatus 10 according to the present embodiment will be described.
First, the width data of the steel plate 31 irradiated with the laser beam LB is obtained. From this width data, the number of laser beam irradiation devices 20 to be used is determined. In this embodiment, as shown in FIG. 1, five laser beam irradiation apparatuses 20 are used.

Then, the position in the width direction of each laser beam irradiation device 20 is determined and moved to a predetermined position using the linear motion device 15. Further, the laser beam irradiation apparatus 20a that is not used is moved to the retracted position.
Furthermore, the scanning length of the laser beam LB in each laser beam irradiation apparatus 20 is determined. The scanning width of the laser beam LB is a value obtained by multiplying the reflection angle of the polygon mirror, that is, the number of polygon surfaces and the focal length of the fθ lens. At this time, the overlapping width d between the laser irradiation lines 32 adjacent in the width direction is adjusted according to the position in the width direction of each laser beam irradiation apparatus 20.
Alternatively, when changing the scanning width of the laser beam LB, the scanning width on the steel plate may be changed by blocking the end of the scanning beam with a shielding plate provided between the fθ lens and the steel plate. Alternatively, the polygon mirror and the fθ lens may be changed.
Alternatively, the scanning width may be changed by changing the mirror reflection angle by a galvano mirror that vibrates the mirror at an arbitrary angle instead of the polygon mirror.
The series of setting operations may be automatically set by a computer using a program.

Next, the laser beam LB is oscillated from the laser device 12. This laser beam LB is transmitted to each laser beam irradiation device 20 via the transmission fiber 13.
In the laser beam irradiation device 20, the laser beam LB is scanned on the steel plate 31 by one surface of the rotating polygon mirror 22. Thereby, a laser irradiation line 32 having a predetermined length is formed on the surface of the steel plate 31. At this time, the laser irradiation line may be a visually identifiable line in which the glass film or insulating film on the surface has evaporated, or may be an invisible line that does not cause the film to evaporate. It only has to be granted.
The interval PL between the laser irradiation lines 32 adjacent to each other in the conveyance direction can be changed by adjusting the conveyance speed of the steel plate 31 and the rotation speed of the rotating polygon mirror 22.
The laser irradiation line 32 can be formed in a groove shape by increasing the output of the laser beam LB, reducing the diameter of the focused beam, or reducing the scanning speed.

Next, an example of the grain-oriented electrical steel sheet manufactured using the grain-oriented electrical steel sheet manufacturing apparatus 10 according to this embodiment will be described with reference to FIGS. 4 and 5.
This grain-oriented electrical steel sheet includes a steel sheet, a glass film formed on the surface of the steel sheet, and an insulating film formed on the glass film. Then, the surface of the grain-oriented electrical steel sheet is irradiated and scanned with a laser beam LB from above the insulating film, so that a laser irradiation line 32 extending substantially orthogonal to the rolling direction as shown in FIG. Is formed.

The laser irradiation lines 32 are formed in a predetermined cycle in the rolling direction, and in a region sandwiched between the two laser irradiation lines 32 and 32 and magnetized in the rolling direction, a magnetic domain in a direction substantially orthogonal to the rolling direction. Subdivide the width.
In the grain-oriented electrical steel sheet shown in FIGS. 4 and 5, the laser irradiation line 32 is divided in the width direction, and the laser irradiation lines 32 and 32 adjacent to each other in the width direction are overlapped by a width d. .

Moreover, the other example of the grain-oriented electrical steel plate manufactured using the manufacturing apparatus of the grain-oriented electrical steel plate which is this embodiment is demonstrated using FIG.6 and FIG.7.
In this grain-oriented electrical steel sheet, the laser irradiation line 32 is divided in the width direction, and the laser irradiation lines 32, 32 adjacent to each other in the width direction are separated by a width d. In addition, when the laser irradiation lines 32 and 32 are separated from each other, the overlapping width d is negative.

Thus, in the grain-oriented electrical steel sheet manufacturing apparatus 10 according to the present embodiment, as described above, the position in the width direction of each laser beam irradiation apparatus 20 and the scanning length of the laser beam LB in each laser beam irradiation apparatus 20 Thus, it is possible to adjust the overlapping width d between the laser irradiation lines 32 and 32 adjacent to each other in the width direction.

  In the grain-oriented electrical steel sheet manufacturing apparatus 10 according to the present embodiment configured as described above, a plurality of laser beam irradiation apparatuses 20 (six in the present embodiment) arranged in the conveying direction of the steel sheet 31; The linear motion device 15 that moves each laser beam irradiation device 20 in the width direction of the steel plate 31 is provided. Therefore, a plurality of laser irradiation lines 32 that are divided in the width direction are formed on the surface of the steel plate 31. Can do. Therefore, the scanning length of the laser beam LB in one laser beam irradiation apparatus 20 can be set short, and even when the wide steel plate 31 is conveyed at a high speed, the laser is emitted at a predetermined interval PL in the rolling direction. The irradiation line 32 can be formed.

Further, the overlapping width d between the laser irradiation lines 32 and 32 adjacent to each other in the width direction can be adjusted by the position in the width direction of each laser beam irradiation apparatus 20 and the scanning length of the laser beam LB in each laser beam irradiation apparatus 20. Therefore, it is possible to stabilize the iron loss and magnetostriction characteristics in the entire width direction of the steel plate 31.

  As an example, using a grain-oriented electrical steel sheet having a thickness of 0.23 mm, the superposed width d was variously changed to obtain the ultimate iron loss value. The grain-oriented electrical steel sheet used has a magnetic flux density of 1.92 T generated in a magnetic field of 0.8 A / m. The laser conditions are a laser power of 200 W, a beam scanning speed of 30 m / s, and a focused beam diameter of φ0.1 mm. The irradiation pitch was 5 mm. The iron loss was measured by cutting the laser irradiated part into a single plate size of 600 mm in the rolling direction and 800 mm in the plate width direction, and measuring the iron loss by applying a magnetic field under the condition that the maximum magnetic flux density was 1.7 T at a frequency of 50 Hz. . The result is shown in FIG. When the overlapping width d of the laser irradiation lines 32 and 32 adjacent to each other in the width direction is in the range of 0 to 10 mm, the lowest iron loss value is shown. In the range of −5 mm to 20 mm, the iron loss increase allowance is 0.01 W / kg. Therefore, the iron loss can be stabilized at a low level in the entire width direction of the steel plate 31.

Further, the magnetostriction characteristics were examined. Magnetostriction is a cause of noise in transformers made of grain-oriented electrical steel sheets. Magnetostrictive velocity level (LVA) was used as an index of magnetostriction. The evaluation method of LVA used the following. First, the steel sheet is cut into a length of 500 mm in the rolling direction and a length of 100 mm in the width direction, and an alternating magnetic field is applied so that the maximum magnetic flux density is 1.7 T in the rolling direction. At this time, the length of the steel sheet changes due to the expansion and contraction of the magnetic domain. The time change of this displacement is measured with a laser displacement meter, and the amplitude Cn of each frequency component fn is obtained by Fourier analysis. Using the A correction coefficient αn of each frequency component, LVA is obtained by the following equation.

LVA = 20 × Log (√ (ρc × 2π × fn × αn × Cn / √2) / Pe0 (dB)

Here, ρc is a specific acoustic resistance, ρc = 400, Pe0 is the minimum audible sound pressure, and Pe0 = 2 × 10 ⁻⁵ (Pa) was used. The A correction coefficient is a value defined by JIS, and is shown in Table 2 of JIS standard C1509-1.
In this example, the same direction back electromagnetic steel sheet sample as above was used, the LVA was measured by changing the overlap width d, and the relationship between the increase from LVA and d when d = 0 mm was examined. As a result, as shown in FIG. 9, when d was 10 mm or less, the LVA increase was 1 dB or less, which was almost negligible. That is, in this range, an increase in magnetostriction (LVA) can be suppressed. Therefore, the magnetostriction characteristic can be stabilized at a low level in the entire width direction of the steel plate 31, and transformer noise can be suppressed.

  Furthermore, in the present embodiment, six laser beam irradiation devices 20 are provided, and the laser irradiation lines 32 are formed by the five laser beam irradiation devices 20 with respect to the entire width of the steel plate 31. A stand laser beam irradiation device 20a is secured as a spare device. The spare laser beam irradiation device 20a is also movable over the entire width of the steel plate 31 by the linear motion device 15. Therefore, the spare laser beam irradiation device 20a is replaced with the laser beam irradiation device 20 in which a trouble has occurred. It can be used immediately.

  In the present embodiment, since the laser device 12 that oscillates the laser beam LB that can be transmitted through the fiber is used, the laser device 12 can be disposed at a position separated from the laser beam irradiation device 20. Therefore, the laser apparatus 12 can be disposed in an air conditioning room or the like, and early deterioration of the laser apparatus 12 can be prevented. Further, the laser beam irradiation apparatus 20 can be reduced in size and weight.

  Further, in the present embodiment, since the laser beam irradiation device 20 is disposed in the vicinity of the support roll 11, there is little vibration of the steel plate 31, and the steel plate 31 moves downward to focus the laser beam irradiation device 20. Irradiation / scanning of the laser beam LB can be performed stably without being greatly separated from the position.

Further, since the linear motion device 15 is provided with a position sensor for specifying the position in the width direction of each laser beam irradiation device 20, the interval in the width direction between the laser beam irradiation devices 20 can be adjusted with high accuracy. .
Furthermore, in this embodiment, since the guide rails 16 of the linear motion device 15 are disposed so as to protrude from both ends in the width direction of the steel plate 31, the spare laser beam irradiation device 20a can be retracted from the top of the steel plate 31. . Therefore, maintenance or the like of the spare laser beam irradiation apparatus 20a can be performed during operation.

<Relationship between laser irradiation line overlap width d and iron loss>
Below, the result evaluated about the relationship between the overlap width d of the laser irradiation line formed in the steel plate and the iron loss is shown.
As shown in FIG. 8, it is determined that the iron loss W17 / 50 can be greatly reduced when the overlapping width d between laser irradiation lines adjacent in the width direction is within a range of −5 to 20 mm. Is done.

<Relationship between laser irradiation line overlap width d and magnetostriction>
Below, the result evaluated about the relationship between the overlap width d of the laser irradiation line formed in the steel plate and magnetostriction is shown.
As shown in FIG. 9, it is confirmed that the increase in LVA can be suppressed by setting the distance d between laser irradiation lines adjacent in the width direction to 10 mm or less.

As mentioned above, although embodiment of this invention was described, this invention is not limited to this, It can change suitably in the range which does not deviate from the technical idea of the invention.
For example, although it has been described that a laser beam capable of fiber transmission is used, the present invention is not limited to this, and a carbon dioxide laser or the like may be used. In this case, the laser beam is transmitted to each laser beam irradiation device by reflection of a plurality of mirrors.
Or it is good also as a structure which installs and moves both a laser apparatus and an irradiation apparatus in a width direction moving mechanism.

  In addition, the laser beam irradiation device has been described as moving in the width direction using a linear motion device, but the present invention is not limited to this, and the laser beam irradiation device is moved in the width direction by another moving mechanism. There may be.

According to the present invention, even when laser processing is performed while conveying a wide steel plate at high speed, the grain-oriented electrical steel sheet having stable iron loss and magnetostriction characteristics in the entire width direction of the steel sheet, A manufacturing apparatus and a manufacturing method can be provided.

10. Manufacturing method of grain-oriented electrical steel sheet 15 Linear motion device (width direction moving mechanism)
20 Laser beam irradiation device 31 Steel plate 32 Laser irradiation line

Claims (1)

A method for producing a grain-oriented electrical steel sheet for producing a grain-oriented electrical steel sheet controlled by irradiating a laser beam,
Using a plurality of laser beam irradiation devices arranged in the conveying direction of the steel sheet, the laser beam is divided and scanned in the width direction of the steel sheet to be conveyed, and a plurality of parts divided in the width direction on the surface of the steel sheet A laser irradiation step of forming laser irradiation lines so that the positions in the transport direction of the laser irradiation lines adjacent in the width direction are different, and the laser beam irradiation apparatus has a laser beam scanning width in the width direction of the steel plate. Can be changed, and
In this laser irradiation step, the steel plates of the laser irradiation lines that are adjacent to each other in the width direction and have different positions in the transport direction depend on the position in the width direction of the laser beam irradiation apparatus and the scanning width of the laser beam of the laser beam irradiation apparatus. A method for producing a grain- oriented electrical steel sheet, wherein the overlapping width in the width direction is adjusted to -5 to 0 mm.

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