WO2023140363A1 - 方向性電磁鋼板、方向性電磁鋼板製造装置、及び方向性電磁鋼板製造方法 - Google Patents
方向性電磁鋼板、方向性電磁鋼板製造装置、及び方向性電磁鋼板製造方法 Download PDFInfo
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- WO2023140363A1 WO2023140363A1 PCT/JP2023/001757 JP2023001757W WO2023140363A1 WO 2023140363 A1 WO2023140363 A1 WO 2023140363A1 JP 2023001757 W JP2023001757 W JP 2023001757W WO 2023140363 A1 WO2023140363 A1 WO 2023140363A1
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- steel sheet
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- 229910001224 Grain-oriented electrical steel Inorganic materials 0.000 title claims abstract description 245
- 238000004519 manufacturing process Methods 0.000 title claims description 75
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 226
- 239000010959 steel Substances 0.000 claims abstract description 226
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Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/36—Removing material
- B23K26/362—Laser etching
- B23K26/364—Laser etching for making a groove or trench, e.g. for scribing a break initiation groove
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/02—Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
- B23K26/06—Shaping the laser beam, e.g. by masks or multi-focusing
- B23K26/062—Shaping the laser beam, e.g. by masks or multi-focusing by direct control of the laser beam
- B23K26/0622—Shaping the laser beam, e.g. by masks or multi-focusing by direct control of the laser beam by shaping pulses
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/02—Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
- B23K26/06—Shaping the laser beam, e.g. by masks or multi-focusing
- B23K26/064—Shaping the laser beam, e.g. by masks or multi-focusing by means of optical elements, e.g. lenses, mirrors or prisms
- B23K26/0643—Shaping the laser beam, e.g. by masks or multi-focusing by means of optical elements, e.g. lenses, mirrors or prisms comprising mirrors
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/02—Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
- B23K26/06—Shaping the laser beam, e.g. by masks or multi-focusing
- B23K26/064—Shaping the laser beam, e.g. by masks or multi-focusing by means of optical elements, e.g. lenses, mirrors or prisms
- B23K26/0648—Shaping the laser beam, e.g. by masks or multi-focusing by means of optical elements, e.g. lenses, mirrors or prisms comprising lenses
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/02—Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
- B23K26/06—Shaping the laser beam, e.g. by masks or multi-focusing
- B23K26/073—Shaping the laser spot
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/08—Devices involving relative movement between laser beam and workpiece
- B23K26/082—Scanning systems, i.e. devices involving movement of the laser beam relative to the laser head
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/12—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/12—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
- C21D8/1277—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties involving a particular surface treatment
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
- H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
- H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
- H01F1/12—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials
- H01F1/14—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys
- H01F1/147—Alloys characterised by their composition
- H01F1/14708—Fe-Ni based alloys
- H01F1/14716—Fe-Ni based alloys in the form of sheets
Definitions
- the present invention relates to a grain-oriented electrical steel sheet, a grain-oriented electrical steel sheet manufacturing apparatus, and a grain-oriented electrical steel sheet manufacturing method.
- a magnetic domain control process for forming grooves on the surface of a grain-oriented electrical steel sheet (hereinafter sometimes simply referred to as steel sheet) has been put into practical use.
- this magnetic domain control three performance factors are particularly important: reduction of core loss, high resistance to repeated bending, and suppression of possible decrease in magnetic flux density. That is, when a steel plate is bent to manufacture a wound transformer core, power loss can be reduced if iron loss can be reduced. Further, if the repeated bending resistance can be improved, the risk of breaking the steel plate at the bent portion can be reduced. Furthermore, if possible reduction in magnetic flux density can be suppressed, the wound transformer core to be manufactured can be miniaturized.
- the iron loss reduction effect is maximized.
- the risk of breakage during bending is the greatest.
- the grooves also have the problem of reducing the magnetic flux density that can be generated when the same magnetizing force is applied.
- the numerical value of iron loss which is an important performance factor of the wound transformer core, is generally defined by W17/50.
- This value is the power loss per unit weight of steel plate (1 kg) when a magnetizing force is forcibly applied to the steel plate by an alternating magnetic field with an alternating frequency of 50 Hz until the magnetic flux density in the steel plate reaches 1.7 T (Tesla), and is expressed in units of W/kg.
- the magnetic flux density that can be generated when a certain magnetizing force is applied to the steel sheet is also an important performance factor as a grain-oriented electrical steel sheet, and generally the numerical value specified in B8 is used. This numerical value is the magnetic flux density generated when a magnetizing force of 800 A/m is applied to the steel plate, and is indicated in units of T (Tesla).
- the direction of groove formation in each divided portion is substantially perpendicular to the rolling direction.
- the iron loss reduction effect is high, but the bending resistance deteriorates.
- a decrease in magnetic flux density is inevitable.
- the linear grooves are divided into about 4 to 5 sections in the plate width direction, portions where no grooves are formed are formed on the surface of portions between adjacent linear grooves. Therefore, there is little decrease in the magnetic flux density at locations where there are no grooves.
- the steel sheet used for the wound transformer core is cut into pieces of about 100 mm to 300 mm in the width direction, it is desirable that the properties of the steel sheet be uniform in the width direction.
- Patent Document 4 discloses a method of forming dents in rows on the surface of a grain-oriented electrical steel sheet.
- the magnetic flux can easily pass through, and suppression of the decrease in the magnetic flux density can be expected to be uniform at each position in the plate width direction.
- the formation direction (extension direction) of the dotted grooves, which are connected in a daisy-chain fashion by connecting both ends of each dent is perpendicular to the rolling direction, the iron loss improvement effect is high, but the repeated bending resistance deteriorates.
- the present invention has been devised in view of the above-mentioned problems, and aims to provide a grain-oriented electrical steel sheet that simultaneously has three performance factors of suppression of deterioration in resistance to repeated bending, suppression of deterioration in magnetic flux density, and reduction in iron loss in magnetic domain control technology that forms grooves on the surface of a grain-oriented electrical steel sheet to improve iron loss.
- Another object of the present invention is to provide a grain-oriented electrical steel sheet manufacturing apparatus and a grain-oriented electrical steel sheet manufacturing method capable of manufacturing the grain-oriented electrical steel sheet.
- the grain-oriented electrical steel sheet according to one aspect of the present invention is A grain-oriented electrical steel sheet having a rolling direction and a sheet width direction orthogonal to the rolling direction along the steel sheet surface,
- the rolling direction matches the direction of easy magnetization of the grain-oriented electrical steel sheet
- the surface of the steel sheet has a point-sequence groove extending along a point-sequence direction that intersects with the sheet width direction,
- the point-sequence groove is a substantially elliptical point-like groove, or a plurality of point-group grooves formed by linearly connecting a plurality of holes are arranged in a straight line, A long axis of the point-like groove or the point group groove intersects the point sequence direction.
- the grain-oriented electrical steel sheet described in (1) or (2) above may employ the following configurations: the dot-sequence groove is composed of the plurality of dot-like grooves; When the length of the point-like groove along the long axis direction is dc [ ⁇ m] and the interval along the plate width direction between the ends of the point-like grooves adjacent to each other is D [ ⁇ m], the following (Formula 4) is satisfied. ⁇ 0.3 ⁇ (D/dc) ⁇ 0.2 (Formula 4)
- the interval D [ ⁇ m] is a positive value when the ends do not overlap each other in the line of sight along the rolling direction, 0 [ ⁇ m] when the ends are in contact with each other at one point, and a negative value when the ends overlap each other.
- the electrical steel sheet according to any one of (1) to (3) above may have the following configuration: the dot-sequence groove is composed of the plurality of dot-like grooves;
- the length of the dotted groove along the long axis direction is dc [ ⁇ m]
- the direction perpendicular to the long axis is the short axis direction of the dotted groove
- the length along the short axis direction of the dotted groove is dL [ ⁇ m]
- the maximum value of the length dc [ ⁇ m] may be 30000 ⁇ m. 10 ⁇ m ⁇ dL ⁇ 300 ⁇ m (Formula 5) dL ⁇ dc (Formula 6)
- the electrical steel sheet according to any one of (1) to (4) above may have the following configuration: the dot-sequence groove is composed of the plurality of dot-like grooves; When the maximum depth of the dotted groove is h [ ⁇ m], the following (Equation 7) is satisfied. 5 ⁇ m ⁇ h ⁇ 100 ⁇ m (Formula 7)
- the electrical steel sheet according to any one of (1) to (5) above may have the following configuration: A plurality of the row-of-spot grooves are formed on the surface of the steel sheet at regular intervals in the rolling direction; The following (Equation 8) is satisfied when PL [mm] is the interval along the rolling direction between the dot-sequence grooves adjacent to each other. 1 mm ⁇ PL ⁇ 10 mm (Formula 8)
- the electrical steel sheet according to any one of (1) to (6) above may have the following configuration:
- Da [mm] is the interval along the plate width direction between the ends of the dot-sequence grooves adjacent to each other at the dividing position
- the following (Equation 9) is satisfied.
- ⁇ 10 mm ⁇ Da ⁇ 2 mm (Formula 9)
- the interval Da [mm] is a positive value when the ends do not overlap each other in the line of sight along the rolling direction, 0 [ ⁇ m] when the ends are in contact with each other at one point, and a negative value when the ends overlap each other.
- a grain-oriented electrical steel sheet manufacturing apparatus includes: An apparatus for manufacturing the grain-oriented electrical steel sheet according to any one of the above (1) to (7) by irradiating the steel sheet surface with a laser beam to form the dot-sequence grooves composed of the dot-shaped grooves, a laser irradiation unit that irradiates the laser beam; a first optical system that makes the spot light of the laser light an elliptical shape and adjusts the direction of the major axis of the elliptical shape formed by the spot light; a scanning mirror that reflects the laser beam adjusted by the first optical system to change the direction of travel, and moves the position on the surface of the steel plate irradiated with the spot light along the scanning direction that intersects the width direction of the steel plate; a second optical system that transmits or reflects the laser beam reflected by the scanning mirror and converges it on the surface of the steel plate; has The first optical system adjusts the direction of the long axis
- a grain-oriented electrical steel sheet manufacturing apparatus includes: An apparatus for manufacturing the grain-oriented electrical steel sheet according to any one of the above (1) to (7) by irradiating the steel sheet surface with a laser beam to form the dot-sequence grooves composed of the dot-shaped grooves, a laser irradiation unit that irradiates the laser beam; a first optical system that makes the spot light of the laser light an elliptical shape and adjusts the direction of the major axis of the elliptical shape formed by the spot light; a second optical system that transmits the laser beam adjusted by the first optical system and focuses it on the surface of the steel plate; a scanning mirror that reflects the laser beam that has passed through the second optical system to change the direction of travel, and moves the position on the surface of the steel sheet irradiated with the spot light along the scanning direction that intersects the width direction of the steel sheet; has The first optical system adjusts the direction of the long axis of the
- a grain-oriented electrical steel sheet manufacturing apparatus includes: An apparatus for manufacturing the grain-oriented electrical steel sheet according to (1) or (2) above by forming the point sequence grooves composed of the point group grooves by irradiating the steel sheet surface with a laser beam, a laser irradiation unit that irradiates the laser beam; a first optical system that makes the spot light of the laser light an elliptical shape and adjusts the direction of the major axis of the elliptical shape formed by the spot light; a beam intensity distribution conversion element that transmits the laser light adjusted by the first optical system and divides the laser light into a plurality of intensity distributions, thereby converting the laser light into a continuous group of continuous spot lights; a scanning mirror that changes the direction of travel by reflecting the continuous spotlights converted by the beam intensity distribution conversion element, and moves a position on the steel sheet surface irradiated with the central position of each group of the continuous spotlights along a scanning direction that intersects the width direction of the steel
- a grain-oriented electrical steel sheet manufacturing method includes: A method for producing a grain-oriented electrical steel sheet according to any one of the above (1) to (7) by forming the dot-sequence grooves composed of the dot-shaped grooves by irradiating the steel plate surface with a laser beam, a first step of forming the spot light of the laser beam into an elliptical shape and adjusting the orientation of the major axis of the elliptical shape formed by the spot light; a second step of changing the traveling direction of the laser beam with the direction of the long axis adjusted, and moving the position on the steel plate surface irradiated with the spot light along the scanning direction intersecting with the width direction of the steel plate; a third step of focusing the spot light on the surface of the steel plate; has In the first step, the direction of the long axis of the ellipse formed by the spot light on the surface of the steel sheet is adjusted in a direction intersecting with the scanning direction, In
- a grain-oriented electrical steel sheet manufacturing method includes: A method for manufacturing the grain-oriented electrical steel sheet according to claim 1 or 2 by forming the point sequence grooves composed of the point group grooves by irradiating the steel sheet surface with a laser beam, a fourth step of forming the spot light of the laser beam into an elliptical shape and adjusting the orientation of the long axis of the elliptical shape formed by the spot light; a fifth step of dividing the laser light with the direction of the major axis adjusted into a plurality of intensity distributions, thereby converting the laser light into a group of continuous spot lights; a sixth step of moving a position on the surface of the steel sheet irradiated with the central position of each group of the continuous spot lights along a scanning direction intersecting the width direction of the steel sheet; a seventh step of converging the continuous spot light on the surface of the steel plate; has In the fifth step, the direction of the continuous direction of the continuous spot light on the surface of
- the pulse frequency of the laser beam is Fs [Hz]
- the moving speed of the spot light on the steel plate surface is Vs [m/s]
- the center-to-center distance of the adjacent point group grooves along the plate width direction is Pc [ ⁇ m]
- the length of the point-like groove along the direction of the long axis is dc [ ⁇ m]
- the interval between the ends of the point-like grooves adjacent to each other along the plate width direction is D [ ⁇ m]
- the long axis is the plate width direction.
- ⁇ g [°] is an angle formed with respect to the plate width direction
- ⁇ s [°] is an angle formed by the direction of the sequence of points with respect to the width direction of the plate.
- Pc D+dc ⁇ cos ⁇ g (Formula 16)
- Pc/cos ⁇ s (Vs/Fs) ⁇ 10 6 (Formula 17)
- a grain-oriented electrical steel sheet that suppresses deterioration in repeated bending resistance, suppresses deterioration in magnetic flux density, and also reduces iron loss. Also, a grain-oriented electrical steel sheet manufacturing apparatus and a grain-oriented electrical steel sheet manufacturing method for manufacturing the grain-oriented electrical steel sheet can be provided.
- FIG. 1 is a diagram showing a grain-oriented electrical steel sheet according to a first embodiment of the present invention, in which (A) is a plan view of the grain-oriented electrical steel sheet, (B) is a partially enlarged view showing dotted grooves formed on the upper surface of the grain-oriented electrical steel sheet, and is an enlarged view of part X in (A), (C) is an explanatory view showing one of the dotted grooves constituting the dotted grooves in a plan view and a cross-sectional view including the long axis of the dotted grooves and perpendicular to the steel sheet surface, and (D) is an enlarged view of the dotted grooves.
- FIG. 2 is a perspective view showing a laser processing device, which is a grain-oriented electrical steel sheet manufacturing device, and a grain-oriented electrical steel sheet being processed according to the first embodiment; 1A is a partial enlarged view of a portion corresponding to FIG. 1B, FIG. 1B is a partially enlarged cross-sectional view of the grain-oriented electrical steel sheet viewed from the C direction, and (C-1) and (C-2) are partially enlarged cross-sectional views of the grain-oriented electrical steel sheet viewed from the L direction.
- FIG. 1A is a partial enlarged view of a portion corresponding to FIG. 1B
- FIG. 1B is a partially enlarged cross-sectional view of the grain-oriented electrical steel sheet viewed from the C direction
- (C-1) and (C-2) are partially enlarged cross-sectional views of the grain-oriented electrical steel sheet viewed from the L direction.
- FIG. 1A is a partial enlarged view of a portion corresponding to FIG. 1B
- FIG. 1B is a partially
- FIG. 1 is a diagram showing the direction of magnetic flux in a conventional grain-oriented electrical steel sheet having grooves, wherein (A) is a partially enlarged plan view of the same grain-oriented electrical steel sheet, (B) is a partially enlarged sectional view of the grain-oriented electrical steel sheet viewed from the C direction, and (C-1) and (C-2) are partially enlarged sectional views of the grain-oriented electrical steel sheet viewed from the L direction.
- FIG. 1 is a diagram showing the direction of magnetic flux in a conventional grain-oriented electrical steel sheet having inclined grooves, wherein (A) is a partially enlarged plan view of the same grain-oriented electrical steel sheet, (B) is a partially enlarged sectional view of the grain-oriented electrical steel sheet viewed from the C direction, and (C-1) and (C-2) are partially enlarged sectional views of the grain-oriented electrical steel sheet viewed from the L direction.
- FIG. 6 is a perspective view showing a laser processing device, which is a grain-oriented electrical steel sheet manufacturing device, and a grain-oriented electrical steel sheet being processed according to a second embodiment of the present invention; FIG.
- FIG. 2 is a diagram showing a fixing jig used when repeatedly bending a grain-oriented electrical steel sheet, in which (A) is a side view showing a state in which the repeated bending is imparted, and (B) is a perspective view showing the relationship between the grain-oriented electrical steel sheet to which the repeated bending is imparted and the row-of-spot grooves.
- FIG. 4 is a graph showing an example, and is a graph showing the dependency of the iron loss values (W17/50) of the grain-oriented electrical steel sheet of the invention example and the grain-oriented electrical steel sheet of the comparative example on the scanning angle ⁇ s formed by the scanning direction of the laser beam and the sheet width direction of the grain-oriented electrical steel sheet.
- FIG. 4 is a graph showing an example, and is a graph showing the dependency of the iron loss values (W17/50) of the grain-oriented electrical steel sheet of the invention example and the grain-oriented electrical steel sheet of the comparative example on the scanning angle ⁇ s formed by the scanning direction of the laser
- FIG. 10 is a graph showing an example, and is a graph showing the dependence of the number of bending times Nb of the grain-oriented electrical steel sheet of the invention example and the grain-oriented electrical steel sheet of the comparative example on the scanning angle ⁇ s formed by the scanning direction of the laser beam and the plate width direction of the grain-oriented electrical steel sheet.
- FIG. 10 is a graph showing an example, with respect to the iron loss value (W17/50) of the grain-oriented electrical steel sheet of the invention example, and is a graph showing the dependency on the inclination angle ⁇ g between the direction of the major axis of the spot light of the laser beam and the sheet width direction of the grain-oriented electrical steel sheet when the scanning angle ⁇ s is set to 10°.
- FIG. 10 is a graph showing an example, and is a graph showing the dependence of the number of bending times Nb of the grain-oriented electrical steel sheet of the invention example and the grain-oriented electrical steel sheet of the comparative example on the scanning angle ⁇ s formed by the scanning direction of the laser beam and
- FIG. 10 is a graph showing an example, and is a graph showing the dependency on the inclination angle ⁇ g formed by the direction of the major axis of the spot light of the laser beam and the plate width direction of the grain-oriented electrical steel sheet when the scanning angle ⁇ s is set to 30° with respect to the iron loss value (W17/50) of the grain-oriented electrical steel sheet of the example of the invention.
- FIG. 10 is a graph showing an example and showing the dependence of the iron loss value (W17/50) of the grain-oriented electrical steel sheet of the invention example on D/dc when the scanning angle ⁇ s is set to 10° and the tilt angle ⁇ g is set to 0°.
- FIG. 10 is a graph showing an example, and is a graph showing the dependency on the inclination angle ⁇ g formed by the direction of the major axis of the spot light of the laser beam and the plate width direction of the grain-oriented electrical steel sheet when the scanning angle ⁇ s is set to 30° with respect to the iron loss value (W17/50
- FIG. 10 is a side view showing a laser processing apparatus, which is a grain-oriented electrical steel sheet manufacturing apparatus, and a grain-oriented electrical steel sheet being processed according to a third embodiment of the present invention
- FIG. 10 is a view showing a grain-oriented electrical steel sheet provided with dot-sequenced grooves formed by the laser processing apparatus of the third embodiment, wherein (A) is a plan view of the grain-oriented electrical steel sheet, (B) is a partial enlarged view showing the dot-sequenced grooves formed on the upper surface of the grain-oriented electrical steel sheet, and (C) is an explanatory diagram showing a plan view and a cross-sectional view perpendicular to the steel sheet surface including the long axis of the dot-shaped grooves, one of the point group grooves constituting the dot-sequenced grooves.
- FIG. 4 is a perspective view showing an example of a galvanomirror used as a scanning mirror instead of a polygon mirror;
- FIG. 11 is an explanatory diagram showing a case where dot-row grooves are formed by dividing in the sheet width direction in Example 4 of the present invention. That is, (A) is a plan view of the grain-oriented electrical steel sheet, and (B) is a partially enlarged view showing the dotted grooves formed on the upper surface of the grain-oriented electrical steel sheet. 10 is a graph showing the dependency of the iron loss value (W17/50) of the grain-oriented electrical steel sheet on the distance Da between adjacent dot-sequence grooves in Example 4 of the present invention.
- FIG. 5 is an explanatory diagram for comparing various groove patterns of the prior art as comparative examples with the groove pattern of the present invention.
- a typical oriented electrical steel sheet is an electrical steel sheet in which the axis of easy magnetization (the ⁇ 100> direction of the body-centered cubic crystal) of the crystal grains of the steel sheet is substantially aligned in the rolling direction of the steel sheet.
- a grain-oriented electrical steel sheet has a structure in which a plurality of magnetic domains having magnetic poles oriented in the rolling direction are arranged with domain walls interposed therebetween. Since such a grain-oriented electrical steel sheet is easily magnetized in the rolling direction, it is suitable as a material for the iron core of a transformer (transformer) in which the magnetic lines of force flow in a substantially constant direction.
- a grain-oriented electrical steel sheet is suitably used as a material for a wound transformer core, which is manufactured by winding steel sheets in multiple layers and then molding them into the shape of an iron core (for example, a quadrangular prism shape having a hollow portion).
- a grain-oriented electrical steel sheet has, for example, a steel sheet body (base iron), glass coatings formed on both front and back surfaces of the steel sheet body, and insulating coatings formed on the glass coating.
- the steel plate body is made of, for example, an iron alloy containing Si.
- the surface of the grain-oriented electrical steel sheet in order to reduce iron loss (that is, for magnetic domain control), is irradiated with a laser beam and scanned in a direction that obliquely intersects the rolling direction of the grain-oriented electrical steel sheet (that is, the conveying direction at the time of manufacture, the longitudinal direction of the steel sheet).
- a plurality of these dot-sequence grooves are formed on the surface of the grain-oriented electrical steel sheet at predetermined intervals along the rolling direction.
- the grain-oriented electrical steel sheet may be simply described as a steel sheet.
- FIG. 1 shows a grain-oriented electrical steel sheet 2 according to the first embodiment, in which dot-sequence grooves 1 are formed on the surface.
- FIG. 2 shows a laser processing apparatus A, which is an example of a grain-oriented electrical steel sheet manufacturing apparatus for processing the grain-oriented electrical steel sheet 2 .
- the grain-oriented electrical steel sheet 2 is an electrical steel sheet to be grooved, and is cold-rolled into a strip having a sheet width Wc.
- the strip-shaped grain-oriented electrical steel sheet 2 is drawn in a rectangular shape, and the direction orthogonal to the rolling direction L is indicated as the sheet width direction C.
- the grain-oriented electrical steel sheet 2 is passed in the rolling direction L by a conveying device (not shown).
- a plurality of dot-sequence grooves 1 shown in FIG. 1(A) formed in the grain-oriented electrical steel sheet 2 have a plan view shape as enlarged in FIG. 1(B).
- Each of the dot-sequenced grooves 1 has a predetermined length (length in the major axis direction of the groove: dc), a groove width (length in the minor axis direction of the groove: dL), and a groove depth (maximum depth of the groove: h). As shown in FIG.
- each dot-sequenced groove 1 is formed so that the direction G of the major axis formed by each dot-shaped groove 1A forming the dot-sequenced groove 1 forms an angle ⁇ g with respect to the sheet width direction C of the grain-oriented electrical steel sheet 2, and is formed such that the angle formed by the dot-sequence direction S and the sheet width direction C of the steel sheet is a scanning angle ⁇ s. That is, the direction G of the long axis of each dot-like groove 1A constituting the dot-sequenced groove 1 is different from the dot-sequence direction S. As shown in FIG.
- the sign of the inclination angle ⁇ g is a positive value when the right hand side of the long axis of the dotted groove 1A on the paper surface is inclined upstream in the transport direction when viewed downstream in the transport direction.
- the sign of the scanning angle ⁇ s is a positive value when the right hand side of the dot sequence direction S on the paper surface is tilted downstream in the transport direction when viewed downstream in the transport direction.
- the point-like groove 1A has a substantially elliptical shape in plan view, and has a maximum groove width (length in the minor axis direction of the point-like groove 1A) dL at the center position from one end side to the other end side in the length direction.
- One end portion 1a and the other end portion 1b of the point-like groove 1A both have an inner surface 1c that is concavely curved in a plan view.
- Inner side surfaces 1d facing each other are formed in a portion of the point-like groove 1A excluding one end portion 1a and the other end portion 1b.
- a bottom surface 1e having a maximum depth of h is formed on the bottom surface side of the dotted groove 1A as shown in FIG. 1(C).
- Bottom surfaces of one end portion 1a and the other end portion 1b of the point-like groove 1A are formed with concave curved inclined surfaces 1f whose bottom gradually becomes shallower near the ends.
- the inner surface 1d may be flat, and in that case, the dotted grooves 1A can be regarded as short linear grooves in a plan view.
- the inner side surface 1d is arcuate, so the point-like groove 1A can be regarded as a short, substantially elliptical groove in a plan view.
- the dot-like grooves 1A are formed so that a pair of dot-like grooves 1A adjacent to each other have a constant interval D along the plate width direction C.
- the interval Pc along the plate width direction C of the central portions in the longitudinal direction of the point-like grooves 1A adjacent to each other is formed to be constant. That is, the dot-sequence grooves 1 are formed by arranging a plurality of dot-like grooves 1A in parallel so as to gradually shift their positions along the dot-sequence direction S at a constant pitch. Further, as shown in FIG. 1A, a plurality of dot-sequence grooves 1 are repeatedly formed at a predetermined pitch PL in the rolling direction L of the grain-oriented electrical steel sheet 2 .
- the dot-sequence direction S in which the dot-sequence grooves 1 are formed is the direction in which the laser beam is scanned by the laser processing apparatus A, which will be described later. Therefore, the point sequence direction S can also be expressed as the scanning direction S of the laser beam.
- the dot-sequence grooves 1 are formed by laser light as will be described later. Therefore, as shown in FIG. 1(B), a plurality of point-like grooves 1A having the same shape are regularly arranged. However, depending on the irradiation state of the laser beam, all the point-like grooves 1A do not have to be completely the same shape, and the end shape and bottom shape of the point-like grooves 1A may be irregular and slightly different from the shapes shown in FIGS. 1(B) and 1(C).
- the dotted grooves 1 in which the dotted grooves 1A are intermittently arranged as shown in FIG. 1(B) are represented by the following (Equation 1) to (Equation 3), when the grain-oriented electrical steel sheet 2 is viewed from above as shown in FIG. It is preferable to have a relationship of
- PL [ ⁇ m] is the interval along the longitudinal direction of the steel sheet between the adjacent dotted grooves 1A.
- a dot row groove 44A divided into a plurality of locations in the width direction may be employed.
- the sheet width Wc is 1000 mm to 1500 mm when the magnetic steel sheet is manufactured in a coil shape on a continuous production line
- the length of one dotted groove 44A is set to 100 mm to 500 mm, and the dotted groove 44A divided into 2 to 10 pieces may be formed.
- interval Da is a negative value, it means that the dot-sequence grooves 44A adjacent to each other overlap in the plate width direction. That is, the interval Da [mm] is a positive value when the ends do not overlap each other in the line of sight along the rolling direction, 0 [ ⁇ m] when the ends are in contact with each other at one point, and a negative value when the ends overlap each other.
- the row-of-spot grooves 1 are formed intermittently at intervals PL in the longitudinal direction of the steel sheet and along the scanning direction S having a predetermined scanning angle ⁇ s with the sheet width direction C. Therefore, the mechanical repeated bending resistance is excellent. Therefore, even if the grain-oriented electrical steel sheet 2 is wound or bent for use as a wound iron core for a transformer, the grain-oriented electrical steel sheet 2 is less likely to break and does not cause defects such as cracks.
- the dot-like grooves 1A forming the dot-sequence grooves 1 are minute circular or substantially elliptical grooves with a length of about several 10 ⁇ m to 1 mm.
- the length of the ellipse may be made longer, but in that case, the number of dotted grooves 1A occupying the width of the plate is reduced.
- a typical small transformer core has a plate width of about 100 mm, but if the width of the dot-like grooves 1A is 30 mm, the number of dot-like grooves 1A becomes 3 to 4 in the plate width, which is extremely small. In that case, since the uniformity of the magnetic flux density in the whole steel plate is lowered, iron loss may increase.
- the major axis length of the dotted groove 1A is about 30 mm at maximum.
- the individual dot-like grooves 1A are formed substantially parallel to each other along the plate width direction C (including an inclination of 0° to 10°). Therefore, the magnetic domain refining effect in the grain-oriented electrical steel sheet 2 can be maximized, and the grain-oriented electrical steel sheet 2 with the maximum iron loss reduction effect can be provided. Further, even if each dot-like groove 1A has an inclination angle .theta.g with respect to the plate width direction C, the inclination angle .theta.g is as small as 10.degree.
- the magnetic flux can pass through the gaps while changing the direction of the magnetic flux vector. Also in the cross-sectional direction, the groove depth is shallow between adjacent point-like grooves, so there is little deterioration of the magnetic flux density on the surface of the steel sheet. Furthermore, the gap between the adjacent point-like grooves 1A is as small as 10 ⁇ m to 1 mm, and a large number of these gaps are uniformly formed along the plate width direction C, so uniform iron loss and magnetic flux density can be obtained in the plate width direction C.
- FIG. 2 is a perspective view showing the laser processing apparatus A of the first embodiment used for forming the dot-like grooves 1A in the grain-oriented electrical steel sheet 2.
- the laser processing apparatus A irradiates the surface of the grain-oriented electrical steel sheet 2 with a pulsed laser beam to form the dot-sequence grooves 1 composed of discrete substantially elliptical dot-shaped grooves 1A extending in the direction intersecting the plate width direction C of the grain-oriented electrical steel sheet 2.
- a laser processing apparatus A includes a laser irradiation unit 3 , a first optical system 5 , a scanning mirror 6 and a second optical system 7 .
- the laser irradiation section 3 includes a laser emission section 8 and a transmission fiber 9, and the transmission fiber 9 is connected to a laser light source (not shown). With this configuration, the laser beam generated by the laser light source can be sent to the laser emitting portion 8 and the laser beam can be emitted from the laser emitting portion 8 .
- the laser light source it is preferable to use a fiber laser or a disk laser in the form of pulse oscillation from the viewpoint of forming a dot-sequence groove.
- a fiber laser or a disk laser in the form of pulse oscillation from the viewpoint of forming a dot-sequence groove.
- various known pulsed laser light sources such as YAG laser and CO 2 laser may be used.
- the laser light source may not be a pulse oscillation laser, and a continuous wave laser may be pulsed by an optical shutter that opens and closes with time.
- the laser beam has high energy, and by irradiating the surface of the grain-oriented electrical steel sheet 2, the surface portion of the grain-oriented electrical steel sheet 2 is melted and scattered, thereby forming grooves.
- the laser beam has an elliptical or linear cross-sectional shape perpendicular to the optical axis at the time when the laser beam is emitted from the laser emitting portion 8 through the first optical system 5 as the laser beam 10 .
- the first optical system 5 is, for example, a combination of a cylindrical lens, a parabolic lens, or a parabolic mirror, and is a so-called elliptical beam collimator that has the function of changing the cross-sectional shape of laser light into an elliptical shape.
- This elliptical beam collimator has a function of adjusting the direction of the major axis of the ellipse formed by the spot light of the laser beam emitted through the first optical system 5 by rotating around the laser optical axis.
- the first optical system 5 is configured by arranging a cylindrical lens collimator (elliptic collimator) 11 made up of a combination of concave and convex cylindrical lenses on the emission side of the laser emission unit 8.
- the laser emitting part 8 and the cylindrical lens collimator 11 are arranged horizontally along the width direction of the grain-oriented electrical steel sheet 2 above the grain-oriented electrical steel sheet 2 being conveyed.
- the cylindrical lens collimator 11 included in the first optical system 5 has the function of converting the cross-sectional shape of the beam into an elliptical shape and rotating the laser beam 10 around the optical axis thereof.
- the elliptical spot light irradiated onto the grain-oriented electrical steel plate 2 is rotated around the laser optical axis, and the direction of the major axis of the ellipse is adjusted.
- a polygon mirror 12 used as a scanning mirror 6 is provided after the cylindrical lens collimator 11 transmits the laser light.
- the scanning mirror 6 may be a galvanomirror.
- the scanning mirror 6 changes the traveling direction of the laser light by reflecting the laser light adjusted by the first optical system 5, and can move the position on the grain-oriented electromagnetic steel sheet 2 irradiated with the spot light of the laser light along the scanning direction S that intersects the width direction of the grain-oriented magnetic steel sheet 2. That is, the scanning angle ⁇ s can be adjusted in the scanning direction of the polygon mirror 12 .
- the shape of the spotlight irradiated onto the surface of the grain-oriented electrical steel sheet 2 is an elliptical shape, it is possible to define the directions of the short axis and the long axis that pass through the center of the spotlight and are orthogonal to each other. Also, the shape of the spot light may be a perfect circle.
- the direction in which the laser beam is irradiated can be changed by rotating the polygon mirror 12 moment by moment, or by changing the tilt angle in the case of a galvanomirror.
- the laser beam 10A reflected by the polygon mirror 12 travels toward the second optical system 7, which will be described later.
- the second optical system 7 has a function of transmitting the laser beam 10A reflected by the scanning mirror 6 and condensing it on the surface of the grain-oriented electrical steel plate 2 after converting it into a focused pulsed laser beam 10B.
- the polygon mirror 12 is a flat regular polygonal prism that has a regular polygonal shape when viewed from the direction of the rotating shaft 13 .
- the polygon mirror 12 has a horizontally extending rotating shaft 13 and rotates around the rotating shaft 13 .
- the outer peripheral surface of the polygon mirror 12 is formed by a plurality of rectangular reflecting surfaces 15 forming the regular polygonal surfaces of the polygon mirror 12 and corners 16 formed by the reflecting surfaces 15 .
- Each reflecting surface 15 is a planar mirror that reflects laser light.
- the polygon mirror 12 is a regular N prism.
- N the number of reflecting surfaces 15
- N the number of reflecting surfaces 15
- the second optical system 7 has an f ⁇ lens (scan lens) 19 .
- the second optical system 7 converges the laser beam 10A incident on the f ⁇ lens 19 from the polygon mirror 12 onto the surface of the grain-oriented electrical steel plate 2 as a pulsed laser beam 10B and irradiates the pulsed laser beam 10B.
- the condensed pulsed laser beam 10B melts, evaporates, and scatters the surface of the grain-oriented electrical steel sheet 2, forming dotted grooves 1A on the surface of the grain-oriented electrical steel sheet 2.
- the second optical system 7 is provided to focus the pulse laser beam 10B on the surface of the grain-oriented electrical steel sheet 2 .
- FIG. 1 The scanning direction S of the pulse laser beam 10B with respect to the surface of the grain-oriented electrical steel sheet 2 is equal to the above-described point sequence direction S, and the scanning direction S is inclined with respect to the sheet width direction C by the scanning angle ⁇ s. It should be noted that even if a flat field lens is used for the second optical system 7 instead of the f.theta. It is also possible to use a parabolic mirror, which is a reflective condensing device, to exhibit a similar function.
- the pulsed laser beam 10B is focused on the surface of the grain-oriented electrical steel sheet 2 so as to form a circular or elliptical spot beam. Then, by the focused pulsed laser beam 10B, a plurality of dotted grooves 1A having an inclination angle ⁇ g of about 0° to 10° with respect to the plate width direction C as shown in FIG. Since the grain-oriented electrical steel sheet 2 is conveyed at a constant speed in the direction of arrow L in FIG. 2, by appropriately adjusting the scanning speed and pulse time width of the pulsed laser beam 10B and the time interval between pulses, it is possible to intermittently continuously form the dot-row grooves 1 in the rolling direction L direction at regular intervals PL (see FIG. 1A).
- the reason why the grooves are formed on the surface of the grain-oriented electrical steel sheet 2 at the scanning angle ⁇ s of about 30° or less is as follows. As described above, when the wound transformer core is manufactured using the grain-oriented electrical steel sheet 2, the formation of the dot-row grooves 1 improves the magnetic properties of the grain-oriented electrical steel sheet 2 and at the same time prevents the grain-oriented electrical steel sheet 2 from breaking or cracking.
- the scan angle ⁇ s may be as small as 10° or less, but if the scan angle ⁇ s approaches 0°, it may cause breakage during the manufacture of the wound transformer core, so it is desirable to avoid an angle close to 0°.
- the diameter of the short axis of the ellipse formed by the spot light of the pulsed laser light 10B immediately before being irradiated onto the grain-oriented electrical steel sheet 2 can be, for example, about several tens of micrometers.
- the long axis of the ellipse can be set to a value of, for example, 30 mm or more, corresponding to the length of the short axis.
- the shape of the dot-shaped grooves 1A formed here is a substantially elliptical shape that intersects the plate width direction by ⁇ g depending on the shape of the focused spot, the inclination of the spot, the pulse time width, and the scanning speed. Also, the interval between the dot-like grooves 1A is adjusted by the repetition frequency of the pulse and the scanning speed.
- FIG. 2 shows an example of an elliptical spot light SP drawn on the surface of the grain-oriented electrical steel sheet 2 when the surface of the grain-oriented electrical steel sheet 2 is irradiated with the pulse laser beam 10B.
- the long axis direction of the spot light SP is tilt-adjusted with respect to the plate width direction C by rotating the cylindrical lens collimator 11 provided in the first optical system 5 .
- the scanning direction S is a direction orthogonal to the rotation axis 13 of the scanning mirror 6, by adjusting the rotation axis 13, the first optical system 5, and the laser emitting unit 8, the scanning angle ⁇ s can be set to an arbitrary angle with respect to the plate width direction C.
- FIG. 1(D) is an enlarged view of one substantially elliptical dotted groove 1A in this embodiment.
- FIG. 1(D) is an enlarged view of one substantially elliptical dotted groove 1A in this embodiment.
- 1(E) is a diagram for explaining that the dot-shaped groove 1A is formed by moving the elliptically condensed spot light in the S direction.
- Tp the pulse time width of the pulse laser
- Vs the spot light moves from E1 to E2 within the pulse time.
- the cylindrical lens collimator 11 is rotationally adjusted to align the elliptical spot light so that the long axis direction of the ellipse is in the G2 direction, which is inclined from the plate width direction C by an angle ⁇ g2.
- the shape of the dot-shaped groove 1A to be formed matches the shape of the outermost circumference of the trajectory of the movement from the elliptical spot E1 to the elliptical spot E2, and becomes a substantially elliptical shape.
- the length of the major axis dc of the dotted groove 1A is the distance between the lower major axis apex P3 of the elliptical spot E1 and the upper apex P2 of the elliptical spot E2 after movement in FIG. 1(E).
- the minor axis dL of the dotted groove 1A is the maximum width in the direction orthogonal to the straight line connecting P2 and P3, and is the distance between the points Q1 and Q2.
- the interval Pc [mm] in the plate width direction C between the adjacent point-like grooves 1A, the interval PL [mm] in the rolling direction L, the interval D [ ⁇ m] between the adjacent point-like grooves 1A are the repetition frequency Fp [Hz] of the pulse laser beam, the scanning speed Vs [m/s] of the pulse laser beam 10B, the number of faces of the scanning mirror 6 N [ ⁇ ], the focal length f [m] of the f ⁇ lens 19, and the threading speed VL [m/ s] are defined by the following (formula 10) to (formula 12).
- the laser processing apparatus A shown in FIG. 2 is a processing apparatus for forming a dotted groove 1 composed of a plurality of dotted grooves 1A having shapes shown in FIGS. 1(A) to (C).
- the first optical system 5 adjusts the direction G of the long axis of the ellipse formed by the spot light of the pulse laser beam 10B on the surface of the grain-oriented electrical steel sheet 2 in a direction different from the scanning direction S (preferably, the direction along the sheet width direction C of the grain-oriented electrical steel sheet 2).
- the second optical system 7 forms dot-like grooves 1A on the surface of the grain-oriented magnetic steel sheet 2 for each spot light of the pulse laser beam 10B focused on the surface of the grain-oriented magnetic steel sheet 2, thereby forming the dot-sequence grooves 1 on the surface of the grain-oriented magnetic steel sheet 2.
- the laser processing apparatus A can be described as an apparatus that performs processing so that the following (Equation 13) to (Equation 15) are established, where ⁇ g [°] is the inclination angle formed by the direction G of the major axis of the ellipse formed by the spot light of the pulse laser beam 10B focused on the surface of the grain-oriented electrical steel plate 2 and the plate width direction C of the steel plate, and ⁇ s [°] is the scanning angle formed by the scanning direction S and the plate width direction C of the steel plate.
- the laser processing apparatus A performs processing so that the following (Equation 16) is established, where dc [ ⁇ m] is the length in the major axis direction of the ellipse formed by the spot light of the pulse laser beam 10B focused on the surface of the grain-oriented electrical steel sheet 2, and D [ ⁇ m] is the interval along the plate width direction of the grain-oriented electrical steel sheet 2 between the adjacent dot-shaped grooves 1A formed for each spot light of the laser beam focused on the surface of the grain-oriented electrical steel sheet 2.
- the laser processing apparatus A can be described as a device that performs processing so that the following (Equation 17) and (Equation 18) are established.
- the laser processing apparatus A can be described as a processing apparatus that performs processing so that the following (Equation 19) is established, where h [ ⁇ m] is the maximum depth of the point-like grooves 1A formed for each spot light of the pulse laser beam 10B focused on the surface of the steel plate.
- the laser processing apparatus A can be described as a laser processing apparatus that performs processing so that the following (Equation 20) holds, where PL [mm] is the interval along the longitudinal direction of the elliptical shape formed by the spot lights of the pulsed laser beam 10B focused on the surface of the grain-oriented electrical steel sheet 2.
- the interval Da [mm] can be described as a laser processing apparatus that processes so that the following (Equation 21) holds.
- the interval Da [mm] is a negative value, it means that adjacent dot-sequence grooves 1 overlap in the sheet width direction. That is, the interval Da [mm] is a positive value when the ends do not overlap each other in the line of sight along the rolling direction, 0 [ ⁇ m] when the ends are in contact with each other at one point, and a negative value when the ends overlap each other.
- this grain-oriented electrical steel sheet manufacturing method for processing the row-of-spot grooves 1 in the grain-oriented electrical steel sheet 2 by the laser processing apparatus A described above has the following steps. That is, this grain-oriented electrical steel sheet manufacturing method has a laser irradiation step of irradiating a laser beam using the laser irradiation unit 3 . Further, this grain-oriented electrical steel sheet manufacturing method has a first optical processing step of adjusting the spot light of the laser light into an elliptical shape using the first optical system 5 and adjusting the direction of the major axis of the ellipse formed by the spot light of the laser light.
- this grain-oriented electrical steel sheet manufacturing method includes a scanning process step of using a scanning mirror 6 to reflect the laser beam 10 adjusted by the first optical system 5 to change the traveling direction of the laser beam 10, thereby moving the position on the steel sheet surface irradiated with the spot light of the laser beam 10 along the scanning direction S, which intersects the sheet width direction C of the grain-oriented electrical steel sheet 2. Furthermore, this grain-oriented electrical steel sheet manufacturing method has a second optical processing step in which a second optical system 7 is used to transmit the laser beam 10A reflected by the scanning mirror 6 and focus it on the surface of the steel sheet.
- the direction G2 of the long axis of the ellipse formed by the spot light of the pulse laser light 10B on the surface of the grain-oriented electrical steel sheet 2 is adjusted in a direction different from the scanning direction S.
- the second optical processing step grooves are formed in the steel sheet surface for each spot light of the pulsed laser beam 10B focused on the steel sheet surface, thereby forming the dot-sequence grooves 1 in the steel sheet surface.
- FIG. 3(A) is a schematic enlarged view of the grain-oriented electrical steel sheet 2 in which the dotted grooves 1A are formed in this embodiment.
- FIG. 3B is a schematic cross-sectional view of the groove forming region viewed from the C direction.
- 3(C-1) and 3(C-2) are schematic cross-sectional views of the groove formation region viewed from the L direction.
- FIG. 3C-1 is a cross-sectional view at a position where no groove is formed
- FIG. 3C-2 is a cross-sectional view along the position where the groove is formed.
- arrows indicate directions of magnetic flux generated in the grain-oriented electrical steel sheet 2 .
- the size of the circle shown in the L-direction cross section represents the size of the magnetic flux density.
- FIGS. 3 and 4 are a schematic enlarged view of the surface showing a conventional configuration in which grooves 21 are continuously formed on the surface of a grain-oriented electrical steel sheet 20 in a direction substantially perpendicular to the rolling direction L, that is, substantially parallel to the sheet width direction C, and a schematic cross-sectional view in the C and L directions.
- FIG. 5 is a cross-sectional view of a conventional configuration in which grooves 22 are continuously formed at an angle of more than 0° from the width direction C, viewed from the same line of sight as in FIGS. 3 and 4 .
- Abnormal eddy current loss which is one component of iron loss, has a positive correlation with the magnetic domain width, so iron loss decreases as the magnetic domain width narrows.
- iron loss is reduced by forming the grooves 21 that act as barriers against the flow direction of the magnetic flux. This barrier effect is highest when the grooves are formed in the direction orthogonal to the magnetic flux direction, and the iron loss reduction effect is high.
- W17/50 which is an index for evaluating iron loss
- W17/50 is an iron loss value when a steel sheet is forcibly magnetized so as to generate a magnetic flux density of 1.7 T on average.
- the grooves make it difficult to generate magnetic flux, the area ratio of the grooves to the entire steel plate is small, so there is almost no difference in the magnetizing force that generates a magnetic flux of 1.7 T depending on the presence or absence of the grooves.
- the magnetic flux density in the lower part of the groove locally increases as shown in FIG. 4(C-2). Since the iron loss is proportional to the square of the magnetic flux density, the iron loss at the bottom of the groove increases. Therefore, the former is more effective in subtracting the reduction in iron loss due to the magnetic domain width phenomenon and the increase in iron loss due to the local increase in the magnetic flux density.
- the magnetic flux density that can be generated when a constant magnetic field is applied is the magnetic flux density generated under a magnetizing force of 800 A/m. If a larger magnetic flux density can be generated with the same magnetizing force, there is an advantage that the transformer iron core can be made smaller. However, when the grooves are formed, the air gap becomes an obstacle to magnetic flux generation, so the magnetic flux density that can be generated with the same magnetizing force is reduced. In terms of mechanical properties, in the manufacturing process of wound transformer cores, bending is performed with an inflection line in the direction parallel to the plate width direction.
- FIG. 5 shows a case where the formation direction of the grooves 22 exceeds 0° with respect to the plate width direction C direction.
- the mechanical strength against bending is increased.
- the barrier effect against the magnetic flux is weaker than in the case of the grooves 21 perpendicular to the rolling direction L as shown in FIG.
- the grooves provide resistance to the flow of magnetic flux, so that the magnetic flux density generated at a constant magnetizing force, eg, B8, is reduced.
- a constant magnetizing force eg, B8
- the present inventors considered that a high iron loss improvement effect can be obtained by forming the groove wall substantially perpendicular to the rolling direction L from a microscopic point of view, and that if the groove formation direction has a certain angle from the plate width direction from a macroscopic point of view, it can withstand mechanical bending. Furthermore, due to the arrangement of the dotted grooves 1A, as shown in FIGS. 3(A) and 3(C-2), from the viewpoint of the surface and the cross section, there are regions where no grooves are formed between the grooves. Therefore, it was thought that the magnetic flux could flow through these regions, and it would be possible to suppress the decrease in the magnetic flux density that could occur with a constant magnetizing force.
- the magnetic domain refining effect can be maximized because the individual dot-like grooves 1A are almost parallel to the sheet width direction C microscopically.
- macroscopically since the formation direction of the point-like grooves 1A has a somewhat large inclination angle with the plate width direction C, stress is less likely to concentrate on the point-like grooves 1A during bending, and the risk of breakage can be suppressed.
- FIG. 6 is a perspective view showing an outline of a laser processing apparatus B according to a second embodiment used for forming dotted grooves 1A in the grain-oriented electrical steel sheet 2.
- the laser processing apparatus B is an apparatus that forms discrete dot-sequence grooves 1 extending in a direction intersecting the sheet width direction C of the grain-oriented electrical steel sheet 2 by irradiating the surface of the grain-oriented electrical steel sheet 2 with a laser beam.
- the laser processing apparatus B includes a laser irradiation section 3 , a first optical system 5 , a second optical system 25 and a scanning mirror 6 .
- the laser irradiation section 3 includes a laser emission section 8 and a transmission fiber 9, as in the structure of the first embodiment.
- the transmission fiber 9 is connected to a laser light source (not shown).
- the second optical system 25 consists of a spherical or aspherical lens or the like, and has a function of transmitting the laser beam 10 adjusted by the first optical system 5, sending it to a scanning mirror 6, which will be described later, and finally condensing it on the surface of the grain-oriented electrical steel plate 2.
- the scanning mirror 6 is composed of a polygon mirror 12 as in the structure of the first embodiment.
- a moving mechanism 27 is provided to support the second optical system 25 and move the second optical system 25 along the optical axis of the laser beam 10 in the forward and backward directions indicated by arrows 26 at high speed.
- the propagation distance of the laser beam 10 from the second optical system 25 to the grain-oriented electromagnetic steel sheet 2 after being reflected by the scanning mirror 6 can be matched with the focal length f of the second optical system 25.
- the polygon mirror 12 scans the surface of the grain-oriented electrical steel sheet 2 along a predetermined scanning direction S with the laser beam 10C that has passed through the second optical system 25, as in the case of the laser processing apparatus A of the first embodiment.
- the moving mechanism 27 moves the second optical system 25 in synchronization with the operation of the polygon mirror 12, and forms the dotted grooves 1A on the surface of the grain-oriented magnetic steel sheet 2 for each spot light of the laser beam 10C focused on the surface of the grain-oriented magnetic steel sheet 2 by the second optical system 25, thereby forming the dot-sequence grooves 1.
- a grain-oriented electrical steel sheet 2 having dotted grooves 1 can be manufactured by a laser processing apparatus B shown in FIG.
- the grain-oriented electrical steel sheet manufacturing method for processing the grooves 1 in the grain-oriented electrical steel sheet 2 by the laser processing apparatus B described above has the following steps. That is, this grain-oriented electrical steel sheet manufacturing method has a laser irradiation step of irradiating the laser beam 10 using the laser irradiation unit 3 . Further, this grain-oriented electrical steel sheet manufacturing method has a first optical processing step of adjusting the spot light of the laser light into an elliptical shape using the first optical system 5 and adjusting the direction of the major axis of the ellipse formed by the spot light of the laser light.
- this grain-oriented electrical steel sheet manufacturing method has a second optical processing step of transmitting the laser beam 10 adjusted by the first optical system 5 using a second optical system 25 whose position with respect to the optical axis direction of the laser beam is changed using a moving mechanism 27, and concentrating the laser beam 10 on the surface of the steel sheet. Furthermore, this grain-oriented electrical steel sheet manufacturing method has a scanning process step of using a scanning mirror 6 to reflect the laser beam 10C that has passed through the second optical system 25 to change the traveling direction of the laser beam 10C, thereby moving the position on the steel sheet surface irradiated with the spot light of the laser beam 10C along the scanning direction S that intersects the sheet width direction C of the grain-oriented electrical steel sheet 2.
- the direction G2 of the major axis of the ellipse formed by the spot light of the laser beam 10C on the surface of the steel sheet is adjusted in a direction different from the scanning direction S and along the width direction C of the grain-oriented electromagnetic steel sheet 2, and the second optical system 25 is moved by the moving mechanism 27 in synchronization with the operation of the scanning mirror 6.
- dot-sequence grooves 1 are formed on the steel plate surface by forming dot-like grooves 1A on the steel plate surface for each spot light of the laser beam 10C focused on the steel plate surface.
- Grain-oriented electrical steel sheets are manufactured through the following manufacturing processes: hot rolling, cold rolling, primary recrystallization/decarburization annealing, secondary recrystallization, flattening annealing, and surface coating. Since there is a high possibility that dot-shaped grooves with a depth of several tens of ⁇ m will disappear during cold rolling, almost the same effect can be obtained regardless of the time point of forming the grooves after the cold rolling process.
- Example 1 of the present invention grooves were formed in the steel sheet after the cold rolling process using a grooving method using laser light, and after that, through all the processes after the primary recrystallization process, a grain-oriented electrical steel sheet product was manufactured. Then, the grain-oriented electrical steel sheet was evaluated in terms of core loss characteristics, bending resistance, and magnetic flux density in comparison with conventional grain-oriented electrical steel sheets.
- the grain-oriented electrical steel sheets were cold-rolled sheets with a width of 100 mm, a length of 500 mm, and a thickness of 0.23 mm. A pulsed laser beam was used as the laser beam.
- the pulse laser used had a laser pulse frequency of 225 kHz, a pulse energy of 7.0 mJ, a pulse time width Tp of 0.5 ⁇ s, a light spot shape of an ellipse, a minor axis diameter of 50 ⁇ m, and a major axis diameter of 80 ⁇ m.
- the beam scanning speed was set to 20 m/s.
- the maximum groove depth h at this time was 35 ⁇ m. That is, in the method of the invention example, one dot-like groove is formed by one pulse of laser light.
- the depth of the minute elliptical grooves in the cross section of the grain-oriented electrical steel sheet 2 has a shallow portion at the longitudinal end of the point-like grooves. Therefore, in order to obtain a groove depth equivalent to that of the continuous groove as an average value, it is desirable that the maximum depth h of the groove center be slightly deeper than that of the continuous groove.
- the iron loss was evaluated as the iron loss value per unit weight (W17/50) [W/kg] at a frequency of 50 Hz and a magnetizing force of 1.7 A/m.
- the grain-oriented magnetic steel sheet 2 was fixed with a jig 28 and repeatedly bent in the L direction. The larger the number of times of bending Nb, the higher the bending strength, which corresponds to a smaller risk of plate breakage when manufacturing the iron core.
- FIG. 7(B) shows the positional relationship between the bent grain-oriented electrical steel sheet 2 and the dot-sequence grooves 1 .
- FIG. 8 shows the evaluation result of the iron loss value (W17/50)
- FIG. 9 shows the evaluation result of the bending number Nb.
- the iron loss reduction effect decreases as the scanning angle ⁇ s increases, so the iron loss value (W17/50) increases as the scanning angle ⁇ s increases.
- the scanning angle ⁇ s>30° the gap between the obliquely arranged minute elliptical grooves increases excessively, so it is thought that the magnetic flux barrier effect, which is the source of iron loss improvement, is reduced, resulting in an increase in iron loss. Therefore, it was found that, in the inventive examples, even if the scanning angle ⁇ s is relatively large, better iron loss than in the comparative example is obtained, and it is particularly preferable that the scanning angle ⁇ s is 30° or less.
- FIG. 9 is a comparison result of examining the dependence of the number of times of bending Nb obtained in the repeated bending test on the scanning angle ⁇ s. It was found that the number of times of bending Nb in the invention examples increases with an increase in the scanning angle ⁇ s, almost the same as in the case of the conventional grain-oriented electrical steel sheet, and that Nb greatly increases when the scanning angle ⁇ s is greater than 0°. Therefore, from the results shown in FIGS. 8 and 9, it was found that the grain-oriented electrical steel sheets of the invention examples can achieve both low iron loss and sufficient resistance to repeated bending.
- Example 2> 10 and 11 show the iron loss values (W17/50) when the inclination angle ⁇ g of the dotted groove is changed in the same direction as the scanning angle ⁇ s when the scanning angle ⁇ s is set to 10° or 30°. Other conditions are the same as in Example 1. As the tilt angle ⁇ g increases from 0°, the magnetic flux barrier effect decreases, so the iron loss value (W17/50) increases only slightly.
- Example 3 The relationship between the interval D representing the degree of superimposition of the point-like grooves along the plate width direction C (the interval between adjacent point-like grooves along the plate width direction C) and the iron loss value (W17/50) was evaluated.
- the distance D is illustrated in FIG. 1(B). If the distance D is positive, the ends of the dot-like grooves adjacent to each other are separated along the sheet width direction C, and if the distance D is negative, the ends of the dot-like grooves adjacent to each other are overlapped.
- FIG. 12 shows the result of examining the influence on the iron loss value (W17/50) represented by the ratio of D representing the degree of overlap and the major axis diameter dc of the dotted groove.
- the L-direction cross-sectional area decreases at the bottom of the grooves, and the magnetic flux density locally increases. This is because the iron loss is proportional to the square of the magnetic flux density, that is, the iron loss value increases locally. Therefore, it is not preferable to set the value of the interval D to an excessive value on the negative side. Therefore, it was found that it is preferable to set the range of D/dc to a range of -0.3 or more and 0.2 or less.
- FIG. 16 is an explanatory diagram of Example 4, which is an example of the invention, in which grooves are formed by dividing the grooves in the width direction into a plurality of grooves on a steel sheet having a width Wc of 1000 mm, which corresponds to the actual coil width, on the assumption that the magnetic steel sheet is continuously manufactured in a coil shape on an actual manufacturing line.
- This example is an example showing the effect of the overlapping width Da of the dot-sequence grooves 44A adjacent to each other.
- each dot row groove 44A was formed by an individual laser processing device.
- the C-direction length of each dot-sequence groove 44A corresponds to the scanning width of each laser processing device, and is about 200 mm at maximum.
- FIG. 1 In the iron loss evaluation, 30 samples of 100 mm ⁇ 500 mm were arbitrarily cut out from each steel plate of 1000 mm ⁇ 2000 mm, the iron loss was measured, and the average value was evaluated. The results are shown in FIG.
- the iron loss shows the lowest value when the overlap width Da is near 0 mm, and when it is larger than 0 mm, that is, the iron loss increases in the direction in which the adjacent dot-sequence grooves 44A move away from each other. It is considered that this is because the influence of the regions between the dot-sequence grooves 44A in which grooves are not formed is increased and the effect of reducing the iron loss is reduced.
- it is smaller than 0 mm that is, when the overlapping width Da of the adjacent dot-sequence grooves 44A in the C direction increases, it is considered that iron loss increases due to an increase in local magnetic flux density at the bottom of the grooves, similar to the effect of the decrease in D/dc shown in Example 3. Therefore, it has been found that there is an appropriate range for the overlapping width Da, and specifically, -10 mm ⁇ Da ⁇ 5 mm.
- FIG. 18 and Table 1 are explanatory diagrams and comparison results comparing the prior art and invention examples with respect to iron loss, bending characteristics, and magnetic flux density, based on the characteristics of the grain-oriented electrical steel sheet before grooving. Cold-rolled grain-oriented electrical steel sheets were prepared, and the characteristics of these groove patterns were compared and evaluated in the same manner as in Example 1 above.
- the magnetic flux density is the magnetic flux density B8 [T] generated when a magnetic field of 0.8 A/m is applied.
- B8 the magnetic flux density
- FIG. 18 is a schematic diagram of the grooves of the compared steel plates. Comparative Example A shows an example in which continuous grooves having a substantially uniform depth are formed in the direction perpendicular to the rolling direction over the entire width of the steel plate. Comparative Example B shows an example in which similar grooves are inclined from the plate width direction C by 10°.
- Comparative Example C is an example in which a series of dotted grooves made up of dotted grooves is formed at an angle of 10° from the plate width direction, and the direction of each dotted groove constituting the dotted grooves is also inclined by 10° in the same direction as the dotted grooves.
- the invention example E is the same as the dot-sequence groove shown in the first example.
- Comparative Example A is compared to the characteristic standard before grooving. Although the iron loss reduction effect is high, the bending strength is low and the reduction in magnetic flux density is large. In Comparative Example B, the flexural strength is relatively high and the amount of magnetic flux density deterioration is small, but the iron loss improvement amount is deteriorated. In Comparative Example C, although bending strength and magnetic flux density characteristics are improved over Comparative Example B, iron loss characteristics are still inferior. On the other hand, invention Example E, low iron loss and high magnetic flux density characteristics are obtained while maintaining bending strength.
- Blocking the flow of magnetic flux by air gaps is the source of the iron loss reduction effect, but in the example of the invention, by forming fine dotted grooves almost perpendicular to the rolling direction, the blockage of magnetic flux is increased and the magnetic domain control effect can be obtained.
- the magnetic domain control effect may be slightly inferior to the case of continuous grooves because the dotted grooves generate portions where grooves are not formed, on the other hand, by uniformly forming minute regions through which magnetic flux can easily pass in the width direction, as shown in FIG. Therefore, the iron loss increase component proportional to the square of the magnetic flux density is small, and the iron loss equivalent to that of Comparative Example A, which had the lowest iron loss among the conventional examples, was obtained.
- FIG. 3 even minute spots through which the magnetic flux easily passes are uniformly present throughout the steel sheet, so that a large decrease in the magnetic flux density can be suppressed.
- the major axis diameter dc of the elliptical groove is 90 ⁇ m and the minor axis diameter dL is 52 ⁇ m, but the dimensions and shape of the elliptical groove are not limited to these values.
- the minor axis diameter dL is an extremely narrow groove width of 10 ⁇ m or less, the effect of inhibiting magnetic flux generation due to magnetic coupling in the groove may be reduced, and the effect of reducing iron loss may be greatly reduced.
- the groove width dL exceeds 300 ⁇ m, the volume of the removed base material will increase significantly, and the magnetic flux generation itself will be hindered.
- the range of the minor axis diameter dL is more preferably 10 ⁇ m to 300 ⁇ m.
- the major axis diameter dc may be longer than the groove width dL, but if the major axis diameter dc exceeds 30000 ⁇ m, that is, 30 mm, for example, when the plate width is cut to about 100 mm to manufacture the transformer core, the number of point-like grooves included in the width is reduced to 3 to 4 places. The flow of magnetic flux is different between the grooves, and the magnetic flux tends to concentrate. If there are only a few such points, the magnetic properties of the plate may become uneven. Therefore, the major axis diameter dc is preferably about 30 mm at maximum.
- the groove depth h is set to 35 ⁇ m in this embodiment, the groove depth is not limited to this. However, if the groove depth h is less than 5 ⁇ m, the magnetic domain control effect cannot be expected, and if the groove is formed deeper than 100 ⁇ m, the generation of magnetic flux is greatly hindered as described above, so it is not preferable for grain-oriented electrical steel sheets that require high magnetic flux density. Therefore, the range of the groove depth h is preferably 5 ⁇ m to 100 ⁇ m.
- the L-direction (rolling direction) interval PL for groove formation was set to 3 mm, but it is not limited to this.
- the pitch PL exceeds 10 mm, the synergistic effect of controlling the magnetic domains of the adjacent grooves in the L direction cannot be expected, and if the pitch PL is less than 1 mm, the generation of magnetic flux is greatly hindered. Therefore, it is preferable that the L-direction pitch PL is in the range of 1 mm to 10 mm.
- FIG. 13 is a perspective view showing the outline of the laser processing apparatus E of the third embodiment used for forming the point group grooves 33A in the grain-oriented electrical steel sheet 2.
- the laser processing apparatus E irradiates the surface of the grain-oriented electrical steel sheet 2 with a laser beam to form a dot-row groove 33 extending in a direction intersecting the sheet width direction C of the grain-oriented electrical steel sheet 2, as shown in FIG.
- a point group groove 33A formed in a grain-oriented electrical steel sheet by the laser processing apparatus E of the present embodiment has a shape different from that of the point group groove 1A shown in FIG.
- FIG. 14 shows a dot sequence groove 33 in which a plurality of point group grooves 33A are intermittently formed.
- the point group groove 33A of the present embodiment has a shape composed of continuous groove portions (elliptical holes 33a) in which a plurality of elliptical holes 33a are connected in a point group manner in a daisy chain in plan view.
- Each elliptical hole 33a is one hole having an inner surface 33b and a bottom surface 33c, and a plurality of elliptical holes 33a are connected in a row in the scanning direction S to form one point group groove 33A.
- the point group groove 33A of the present embodiment is an assembly of a plurality of elliptical holes 33a
- the configuration and formation process of the point sequence groove 1 made up of the point-like grooves 1A described above are the same. That is, the point group grooves 33A are intermittently aligned with a predetermined pitch along the scanning direction S, the inclination angle ⁇ g of the long axis of the point group grooves 33A with respect to the plate width direction C is defined, the scanning angle ⁇ s is defined, the length dc in the long axis direction of the point group grooves 33A is defined, and the short axis length dc of the point group grooves 33A is defined, which are equivalent to the point-like grooves 1A shown in FIG.
- the dot-sequenced grooves 33 which are aggregates of the point-group grooves 33A, are aligned in the longitudinal direction of the grain-oriented electrical steel sheet 2 with a predetermined interval PL is also the same as the point-sequenced grooves 1 described above. It is also the same that the groove shape is formed by moving the spot light condensed into a point group at the speed Vs during the pulse time Tp.
- the laser processing apparatus E shown in FIG. 13 includes a laser irradiation unit 3, a first optical system 5, a diffraction grating element (Diffractive Optics) 34 as a beam intensity distribution conversion element, a scanning mirror 6 (polygon mirror 12), and a third optical system 35.
- the laser irradiation section 3 has a laser emission section 8 and a transmission fiber 9 as in the structure of the first embodiment, and the transmission fiber 9 is connected to a laser light source (not shown).
- the first optical system 5 arranged on the emission side of the laser irradiation unit 3 is composed of a cylindrical lens collimator 11 as in the laser processing apparatus A described above.
- the third optical system 35 has an f ⁇ lens (scan lens) 19 in the same manner as the structure of the first embodiment and the second optical system 7 .
- a diffraction grating element 34 is provided as a beam intensity distribution conversion element between the output side of the cylindrical lens collimator 11 and the polygon mirror 12 .
- the beam intensity distribution converting element 34 splits the spatial intensity distribution of the laser light into a plurality of continuous intensity distributions of two or more by diffraction.
- it has a function of converting into continuous spot light (spot light that can be formed by point group grooves 33A with continuous elliptical holes 33a as shown in FIG. 14C), which is continuous in a group (as shown in FIG. 14B, the point group grooves 33A are intermittently continuous).
- An example of intensity distribution is shown in FIG. FIG.
- the beam intensity distribution conversion element 34 is an element that converts or divides the intensity distribution by diffraction and transmission of laser light, and can be combined with an f ⁇ lens to form a group of intensity distributions at the focal point (surface of the grain-oriented electrical steel sheet 2).
- the laser beam 10D is sent to the polygon mirror 12, reflected by the polygon mirror 12, and scanned.
- the scanned laser beam 10E is converged as a laser beam 10F on the surface of the steel plate via a third optical system 35 having the same configuration as the second optical system 7 of the first embodiment, so that continuous point group grooves 33A can be formed on the surface of the grain-oriented electrical steel plate 2.
- the laser beam 10F focused on the steel plate surface of the grain-oriented electrical steel plate 2 exhibits a spatial intensity distribution having six consecutive intensity distributions as shown in FIG.
- a single-intensity pulsed laser beam can be converted into an intensity distribution having two or more peaks at the focal point (steel plate surface) by combining the beam intensity distribution conversion element 34 and the f ⁇ lens 19. Therefore, individual point group grooves 33A can be configured as aggregates of a plurality of elliptical holes 33a.
- the laser light to be incident on the beam intensity distribution conversion element 34 can be, for example, Gaussian distributed laser light having a high central intensity and a single low peak at the ends.
- a laser beam having a flat top mode distribution as shown in FIG. 13B may be used.
- the grain-oriented electrical steel sheet manufacturing method for processing the grooves 1 in the grain-oriented electrical steel sheet 2 by the laser processing apparatus E described above has the following steps. That is, this grain-oriented electrical steel sheet manufacturing method has a laser irradiation step of irradiating the laser beam 10 using the laser irradiation unit 3 . Further, this grain-oriented electrical steel sheet manufacturing method has a first optical processing step of adjusting the spot light of the laser beam 10 into an elliptical shape using the first optical system 5 and adjusting the direction of the major axis of the ellipse formed by the spot light of the laser beam 10.
- this grain-oriented electrical steel sheet manufacturing method has a laser splitting step of transmitting the laser beam 10 and adjusting the spatial intensity distribution of the laser beam 10 into a plurality of continuous intensity distributions of two or more using the beam intensity distribution conversion element 34 . Furthermore, this grain-oriented electrical steel sheet manufacturing method includes a scanning process step of using a scanning mirror 6 to reflect the laser beam 10 adjusted by the beam splitting element 34 to change the traveling direction of the laser beam 10, thereby moving the position on the steel sheet irradiated with the spot light of the laser beam 10 along the scanning direction S, which intersects the sheet width direction of the grain-oriented electrical steel sheet 2. Furthermore, this grain-oriented electrical steel sheet manufacturing method has a third optical processing step in which a third optical system 35 is used to transmit the laser beam reflected by the scanning mirror 6 and focus it on the surface of the steel sheet.
- the direction G of the long axis of the ellipse formed by the spot light of the laser beam 10F on the steel plate surface is adjusted in a direction different from the scanning direction S and along the plate width direction C of the steel plate.
- grooves are formed in the surface of the steel sheet for each spot light of the laser beam 10F focused on the surface of the steel sheet, thereby forming the dot-sequence grooves 33 in the surface of the steel sheet.
- the rotary polygon mirror 12 used as the scanning mirror 6 in the previous embodiment may be replaced with a galvanomirror 30 configured as shown in FIG.
- a galvanomirror 30 shown in FIG. 15 is rotationally driven in the direction of the arrow in FIG.
- the laser beam can be scanned by changing the reflection direction of the laser beam according to the rotation angle of the galvanomirror 30 .
- the processing method is not limited to laser processing.
- the grooves may be mechanically formed using a toothed roll having an uneven shape corresponding to an appropriate dot row groove pattern, or a toothed press.
- it may be formed by an etching method in which a resist film is applied to the surface of the steel sheet in an appropriate pattern and immersed in an etchant to chemically form an appropriate groove pattern.
- a fine processing method using an electron beam may be used as a non-contact processing method.
- the grain-oriented electrical steel sheet according to one aspect of the present invention is A grain-oriented electrical steel sheet having a rolling direction and a sheet width direction orthogonal to the rolling direction along the steel sheet surface,
- the rolling direction matches the direction of easy magnetization of the grain-oriented electrical steel sheet
- the surface of the steel sheet has a point-sequence groove extending along a point-sequence direction that intersects with the sheet width direction,
- the point-sequence groove is a substantially elliptical point-like groove, or a plurality of point-group grooves formed by linearly connecting a plurality of holes are arranged in a straight line, A long axis of the point-like groove or the point group groove intersects the point sequence direction.
- the grain-oriented electrical steel sheet described in (1) or (2) above may employ the following configurations: the dot-sequence groove is composed of the plurality of dot-like grooves; When the length of the point-like groove along the long axis direction is dc [ ⁇ m] and the interval along the plate width direction between the ends of the point-like grooves adjacent to each other is D [ ⁇ m], the following (Formula 4) is satisfied. ⁇ 0.3 ⁇ (D/dc) ⁇ 0.2 (Formula 4)
- the interval D [ ⁇ m] is a positive value when the ends do not overlap each other in the line of sight along the rolling direction, 0 [ ⁇ m] when the ends are in contact with each other at one point, and a negative value when the ends overlap each other.
- the electrical steel sheet according to any one of (1) to (3) above may have the following configuration: the dot-sequence groove is composed of the plurality of dot-like grooves;
- the length of the dotted groove along the long axis direction is dc [ ⁇ m]
- the direction perpendicular to the long axis is the short axis direction of the dotted groove
- the length along the short axis direction of the dotted groove is dL [ ⁇ m]
- the maximum value of the length dc [ ⁇ m] may be 30000 ⁇ m. 10 ⁇ m ⁇ dL ⁇ 300 ⁇ m (Formula 5) dL ⁇ dc (Formula 6)
- the electrical steel sheet according to any one of (1) to (4) above may have the following configuration: the dot-sequence groove is composed of the plurality of dot-like grooves; When the maximum depth of the dotted groove is h [ ⁇ m], the following (Equation 7) is satisfied. 5 ⁇ m ⁇ h ⁇ 100 ⁇ m (Formula 7)
- the electrical steel sheet according to any one of (1) to (5) above may have the following configuration: A plurality of the row-of-spot grooves are formed on the surface of the steel sheet at regular intervals in the rolling direction; The following (Equation 8) is satisfied when PL [mm] is the interval along the rolling direction between the dot-sequence grooves adjacent to each other. 1 mm ⁇ PL ⁇ 10 mm (Formula 8)
- the electrical steel sheet according to any one of (1) to (6) above may have the following configuration:
- Da [mm] is the interval along the plate width direction between the ends of the dot-sequence grooves adjacent to each other at the dividing position
- the following (Equation 9) is satisfied.
- ⁇ 10 mm ⁇ Da ⁇ 2 mm (Formula 9)
- the interval Da [mm] is a positive value when the ends do not overlap each other in the line of sight along the rolling direction, 0 [ ⁇ m] when the ends are in contact with each other at one point, and a negative value when the ends overlap each other.
- a grain-oriented electrical steel sheet manufacturing apparatus includes: An apparatus for manufacturing the grain-oriented electrical steel sheet according to any one of the above (1) to (7) by irradiating the steel sheet surface with a laser beam to form the dot-sequence grooves composed of the dot-shaped grooves, a laser irradiation unit that irradiates the laser beam; a first optical system that makes the spot light of the laser light an elliptical shape and adjusts the direction of the major axis of the elliptical shape formed by the spot light; a scanning mirror that reflects the laser beam adjusted by the first optical system to change the direction of travel, and moves the position on the surface of the steel plate irradiated with the spot light along the scanning direction that intersects the width direction of the steel plate; a second optical system that transmits or reflects the laser beam reflected by the scanning mirror and converges it on the surface of the steel plate; has The first optical system adjusts the direction of the long axis
- a grain-oriented electrical steel sheet manufacturing apparatus includes: An apparatus for manufacturing the grain-oriented electrical steel sheet according to any one of the above (1) to (7) by irradiating the steel sheet surface with a laser beam to form the dot-sequence grooves composed of the dot-shaped grooves, a laser irradiation unit that irradiates the laser beam; a first optical system that makes the spot light of the laser light an elliptical shape and adjusts the direction of the major axis of the elliptical shape formed by the spot light; a second optical system that transmits the laser beam adjusted by the first optical system and focuses it on the surface of the steel plate; a scanning mirror that reflects the laser beam that has passed through the second optical system to change the direction of travel, and moves the position on the surface of the steel sheet irradiated with the spot light along the scanning direction that intersects the width direction of the steel sheet; has The first optical system adjusts the direction of the long axis of the
- a grain-oriented electrical steel sheet manufacturing apparatus includes: An apparatus for manufacturing the grain-oriented electrical steel sheet according to (1) or (2) above by forming the point sequence grooves composed of the point group grooves by irradiating the steel sheet surface with a laser beam, a laser irradiation unit that irradiates the laser beam; a first optical system that makes the spot light of the laser light an elliptical shape and adjusts the direction of the major axis of the elliptical shape formed by the spot light; a beam intensity distribution conversion element that transmits the laser light adjusted by the first optical system and divides the laser light into a plurality of intensity distributions, thereby converting the laser light into a continuous group of continuous spot lights; a scanning mirror that changes the direction of travel by reflecting the continuous spotlights converted by the beam intensity distribution conversion element, and moves a position on the steel sheet surface irradiated with the central position of each group of the continuous spotlights along a scanning direction that intersects the width direction of the steel
- a grain-oriented electrical steel sheet manufacturing method includes: A method for producing a grain-oriented electrical steel sheet according to any one of the above (1) to (7) by forming the dot-sequence grooves composed of the dot-shaped grooves by irradiating the steel plate surface with a laser beam, a first step of forming the spot light of the laser beam into an elliptical shape and adjusting the orientation of the major axis of the elliptical shape formed by the spot light; a second step of changing the traveling direction of the laser beam with the direction of the long axis adjusted, and moving the position on the steel plate surface irradiated with the spot light along the scanning direction intersecting with the width direction of the steel plate; a third step of focusing the spot light on the surface of the steel plate; has In the first step, the direction of the long axis of the ellipse formed by the spot light on the surface of the steel sheet is adjusted in a direction intersecting with the scanning direction, In
- a grain-oriented electrical steel sheet manufacturing method includes: A method for manufacturing the grain-oriented electrical steel sheet according to claim 1 or 2 by forming the point sequence grooves composed of the point group grooves by irradiating the steel sheet surface with a laser beam, a fourth step of forming the spot light of the laser beam into an elliptical shape and adjusting the orientation of the long axis of the elliptical shape formed by the spot light; a fifth step of dividing the laser light with the direction of the major axis adjusted into a plurality of intensity distributions, thereby converting the laser light into a group of continuous spot lights; a sixth step of moving a position on the surface of the steel sheet irradiated with the central position of each group of the continuous spot lights along a scanning direction intersecting the width direction of the steel sheet; a seventh step of converging the continuous spot light on the surface of the steel plate; has In the fifth step, the direction of the continuous direction of the continuous spot light on the surface of
- the pulse frequency of the laser beam is Fs [Hz]
- the moving speed of the spot light on the steel plate surface is Vs [m/s]
- the center-to-center distance of the adjacent point group grooves along the plate width direction is Pc [ ⁇ m]
- the length of the point-like groove along the direction of the long axis is dc [ ⁇ m]
- the interval between the ends of the point-like grooves adjacent to each other along the plate width direction is D [ ⁇ m]
- the long axis is the plate width direction.
- ⁇ g [°] is an angle formed with respect to the plate width direction
- ⁇ s [°] is an angle formed by the direction of the sequence of points with respect to the width direction of the plate.
- Pc D+dc ⁇ cos ⁇ g (Formula 16)
- Pc/cos ⁇ s (Vs/Fs) ⁇ 10 6 (Formula 17)
- each aspect of the present invention it is possible to provide a grain-oriented electrical steel sheet that suppresses deterioration in repeated bending resistance, suppresses deterioration in magnetic flux density, and also reduces iron loss. Also, a grain-oriented electrical steel sheet manufacturing apparatus and a grain-oriented electrical steel sheet manufacturing method for manufacturing the grain-oriented electrical steel sheet can be provided. Therefore, industrial applicability is great.
- A, B, E... Laser processing device C... Plate width direction, G... Long axis direction, L... Rolling direction (longitudinal direction), S... Scanning direction (dot sequence direction), PL... Spacing, ⁇ g... Tilt angle, ⁇ s... Scanning angle, 1... Dot-sequence groove, 1A... Dot-like groove, 2... Oriented electromagnetic steel sheet, 3... Laser irradiation unit, 5... First optical system, 6... Scanning mirror, 7... Second optical system, 10, 10A, 10B, 10D, 1 0F... Pulse laser light (laser light), 11... Cylindrical lens collimator, 12... Polygon mirror, 19... f ⁇ lens, 30... Galvanomirror, 33... Dot-sequence groove, 33A... Groove, 33a... Elliptical hole, 34... Beam splitting element (diffraction element), 35... Third optical system.
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Abstract
Description
本願は、2022年1月20日に、日本国に出願された特願2022-007442号に基づき優先権を主張し、その内容をここに援用する。
すなわち、鋼板を曲げて巻きトランス鉄芯を製造する場合、鉄損を低減できれば、電力ロスが低減できる。また、耐繰返し曲げ特性を向上できれば、鋼板がその曲げ加工部で破断するリスクを低減できる。さらに、発生し得る磁束密度低下を抑制できれば、製造する巻きトランス鉄芯を小型化することができる。
ここで、巻きトランス鉄心の重要な性能因子である鉄損の数値は、一般に、W17/50によって規定される数値が使われる。この数値は、交流周波数が50Hzである交流磁場によって鋼板内の磁束密度が1.7T(テスラ)になるまで強制的に磁化力を鋼板に印加した際の、鋼板単位重量(1kg)あたりの電力損失であり、W/kgの単位で示される。
例えばレーザ加工法では、1m程度あるコイルの板幅方向を4~10か所の区分に分割し、各部に対応する位置にレーザ加工装置を配置して連続溝を各部毎に形成する方法が知られている。また楕円スポット光を走査して溝を形成する方法も知られている。
ここで、線状溝を板幅方向において4~5ヶ所程度の区分に分割する場合は、互いに隣接する線状溝間の部分の表面に、溝が形成されない箇所が形成される。そのため、溝が無い箇所での磁束密度低下は少ない。しかし、そのような箇所は板幅方向で数ヶ所しかないため、板全体で均一に磁束密度低下を抑制することはできない。なお、巻きトランス鉄芯に使用する鋼板は、その板幅方向において100mm~300mm程度に切断して使用するため、鋼板の幅方向における特性が均一であることが望ましい。
また、点列溝の形成方向を圧延方向に対して傾斜させると耐繰り返し曲げ特性は向上するが鉄損改善効果が低下するという問題がある。すなわち、従来の点列溝では、磁束密度の劣化代は抑えられても、鉄損抑制と耐繰り返し曲げ強度の両立は、連続溝の場合と同様に達成できなかった
よって、連続溝、あるいは従来の点列溝を形成する従来技術では、低い鉄損、高い耐繰り返し曲げ特性、及び高い磁束密度の3つ全てを同時に満足することはできなかった。
(1)すなわち、本発明の一態様に係る方向性電磁鋼板は、
鋼板表面に沿って、圧延方向と、前記圧延方向に直交する板幅方向とを有する方向性電磁鋼板であって、
前記圧延方向が、前記方向性電磁鋼板の磁化容易方向と一致しており、
前記鋼板表面に、前記板幅方向と交差する点列方向に沿って延在する点列溝を有し、
前記点列溝が、略楕円形の点状溝、または、複数の穴が直線的に連なって形成された点群溝が、複数、直線的に並んで構成され、
前記点状溝または前記点群溝の長軸が、前記点列方向に対して交差している。
前記長軸が前記板幅方向に対してなす角度をθg[°]とし、前記点列方向が前記板幅方向に対してなす角度をθs[°]としたときに、下記(式1)~(式3)を満たしてもよい。
0°≦|θg|≦10° …(式1)
0°<|θs|≦30° …(式2)
|θg|≦|θs| …(式3)
前記点列溝が、前記複数の点状溝で構成され;
前記点状溝の前記長軸の方向に沿った長さをdc[μm]とし、互いに隣接する前記点状溝の端部同士の前記板幅方向に沿った間隔をD[μm]としたときに、下記(式4)を満たす。
-0.3≦(D/dc)≦0.2 …(式4)
ここで、前記間隔D[μm]は、前記圧延方向に沿って見た視線において、前記端部同士間が互いに重なっていない場合を正の値とし、前記端部同士間が一点で接している場合を0[μm]とし、前記端部同士間が互いに重なっている場合を負の値とする。
前記点列溝が、前記複数の点状溝で構成され;
前記点状溝の前記長軸の方向に沿った長さをdc[μm]とし、前記長軸に直交する方向を前記点状溝の短軸方向とし、前記点状溝の前記短軸方向に沿った長さをdL[μm]としたときに、下記(式5)及び(式6)を満たす。なお、長さdc[μm]の最大値を30000μmとしてもよい。
10μm≦dL≦300μm …(式5)
dL≦dc …(式6)
前記点列溝が、前記複数の点状溝で構成され;
前記点状溝の最大深さをh[μm]としたときに、下記(式7)を満たす。
5μm≦h≦100μm …(式7)
前記鋼板表面上に、前記点列溝が複数本、前記圧延方向に等間隔で形成され;
互いに隣接する前記点列溝の前記圧延方向に沿った間隔をPL[mm]としたときに、下記(式8)を満たす。
1mm≦PL≦10mm ・・・(式8)
前記点列溝が前記板幅方向で2つ以上に分割されており、分割位置において互いに隣接する前記点列溝の端部間の前記板幅方向に沿った間隔をDa[mm]としたときに、下記(式9)を満たす。
-10mm≦Da≦2mm …(式9)
ここで、前記間隔Da[mm]は、前記圧延方向に沿って見た視線において、前記端部同士間が互いに重なっていない場合を正の値とし、前記端部同士間が一点で接している場合を0[μm]とし、前記端部同士間が互いに重なっている場合を負の値とする。
前記鋼板表面にレーザ光を照射することによって前記点状溝で構成された前記点列溝を形成して上記(1)~(7)のいずれか一項に記載の方向性電磁鋼板を製造する装置であって、
前記レーザ光を照射するレーザ照射部と;
前記レーザ光のスポット光を楕円形とし、前記スポット光のなす前記楕円形の前記長軸の向きを調整する第1光学系と;
前記第1光学系で調整された前記レーザ光を反射することで進行方向を変化させ、前記スポット光が照射される前記鋼板表面上の位置を、前記板幅方向と交差する走査方向に沿って移動させる走査ミラーと;
前記走査ミラーで反射した前記レーザ光を透過または反射し、前記鋼板表面に集光させる第2光学系と;
を有し、
前記第1光学系は、前記鋼板表面における前記スポット光がなす前記楕円形の前記長軸の向きを、前記走査方向と交差する方向に調整し、
前記第2光学系で前記鋼板表面に集光される前記スポット光毎に、前記鋼板表面に前記点状溝を形成することで、前記鋼板表面に前記点列溝を形成し、
前記レーザ光のパルス周波数をFs[Hz]とし、前記鋼板表面における前記スポット光の移動速度をVs[m/s]とし、互いに隣り合う前記点状溝の前記板幅方向に沿った中心間距離をPc[μm]とし、前記点状溝の前記長軸の方向に沿った長さをdc[μm]とし、互いに隣接する前記点状溝の端部同士の前記板幅方向に沿った間隔をD[μm]とし、前記長軸が前記板幅方向に対してなす角度をθg[°]とし、前記点列方向が前記板幅方向に対してなす角度をθs[°]としたときに、下記(式10)および(式11)を満たす。
Pc=D+dc×cosθg …(式10)
Pc/cosθs=(Vs/Fs)×106…(式11)
前記鋼板表面にレーザ光を照射することによって前記点状溝で構成された前記点列溝を形成して上記(1)~(7)のいずれか一項に記載の方向性電磁鋼板を製造する装置であって、
前記レーザ光を照射するレーザ照射部と;
前記レーザ光のスポット光を楕円形とし、前記スポット光がなす前記楕円形の前記長軸の向きを調整する第1光学系と;
前記第1光学系で調整された前記レーザ光を透過し、前記鋼板表面に集光させる第2光学系と;
前記第2光学系を透過した前記レーザ光を反射することで進行方向を変化させ、前記スポット光が照射される前記鋼板表面上の位置を、前記板幅方向と交差する走査方向に沿って移動させる走査ミラーと;
を有し、
前記第1光学系は、前記鋼板表面における前記スポット光がなす前記楕円形の前記長軸の向きを、前記走査方向と交差する方向に調整し、
前記第2光学系で前記鋼板表面に集光される前記スポット光毎に、前記鋼板表面に前記点状溝を形成することで、前記鋼板表面に前記点列溝を形成し、
前記レーザ光のパルス周波数をFs[Hz]とし、前記鋼板表面における前記スポット光の移動速度をVs[m/s]とし、互いに隣り合う前記点状溝の前記板幅方向に沿った中心間距離をPc[μm]とし、前記点状溝の前記長軸の方向に沿った長さをdc[μm]とし、互いに隣接する前記点状溝の端部同士の前記板幅方向に沿った間隔をD[μm]とし、前記長軸が前記板幅方向に対してなす角度をθg[°]とし、前記点列方向が前記板幅方向に対してなす角度をθs[°]としたときに、下記(式12)および(式13)を満たす。
Pc=D+dc×cosθg …(式12)
Pc/cosθs=(Vs/Fs)×106…(式13)
前記鋼板表面にレーザ光を照射することによって前記点群溝で構成された前記点列溝を形成して上記(1)または(2)に記載の方向性電磁鋼板を製造する装置であって、
前記レーザ光を照射するレーザ照射部と;
前記レーザ光のスポット光を楕円形とし、前記スポット光がなす前記楕円形の前記長軸の向きを調整する第1光学系と;
前記第1光学系で調整された前記レーザ光を透過し、前記レーザ光を複数の強度分布に分割することで、群状に連続する、連続したスポット光に変換するビーム強度分布変換素子と;
前記ビーム強度分布変換素子で変換された前記連続したスポット光を反射することで進行方向を変化させ、前記連続したスポット光の群毎の中心位置が照射される前記鋼板表面上の位置を、前記板幅方向と交差する走査方向に沿って移動させる走査ミラーと;
前記走査ミラーで反射した前記連続したスポット光を透過し、前記鋼板表面に集光させる第3光学系と;
を有し、
前記第1光学系は、前記鋼板表面における前記連続したスポット光の連続する方向の向きを、前記走査方向と交差する方向に調整し、
前記第3光学系で前記鋼板表面に集光される前記連続したスポット光毎に、前記鋼板表面に前記点群溝を形成することで、前記鋼板表面に前記点列溝を形成し、
前記レーザ光のパルス周波数をFs[Hz]とし、前記鋼板表面における前記スポット光の移動速度をVs[m/s]とし、互いに隣り合う前記点群溝の前記板幅方向に沿った中心間距離をPc[μm]とし、前記点状溝の前記長軸の方向に沿った長さをdc[μm]とし、互いに隣接する前記点状溝の端部同士の前記板幅方向に沿った間隔をD[μm]とし、前記長軸が前記板幅方向に対してなす角度をθg[°]とし、前記点列方向が前記板幅方向に対してなす角度をθs[°]としたときに、下記(式14)および(式15)を満たす。
Pc=D+dc×cosθg …(式14)
Pc/cosθs=(Vs/Fs)×106…(式15)
前記鋼板表面にレーザ光を照射することによって前記点状溝で構成された前記点列溝を形成して上記(1)~(7)のいずれか一項に記載の方向性電磁鋼板を製造する方法であって、
前記レーザ光のスポット光を楕円形とし、前記スポット光がなす前記楕円形の前記長軸の向きを調整する第1工程と;
前記長軸の向きが調整された前記レーザ光の進行方向を変化させ、前記スポット光が照射される前記鋼板表面上の位置を、前記板幅方向と交差する走査方向に沿って移動させる第2工程と;
前記スポット光を前記鋼板表面に集光させる第3工程と;
を有し、
前記第1工程では、前記鋼板表面における前記スポット光がなす前記楕円形の前記長軸の向きを、前記走査方向と交差する方向に調整し、
前記第3工程では、前記鋼板表面に集光される前記スポット光毎に、前記鋼板表面に前記点状溝を形成することで、前記鋼板表面に前記点列溝を形成する。
前記鋼板表面にレーザ光を照射することによって前記点群溝で構成された前記点列溝を形成して請求項1または2に記載の方向性電磁鋼板を製造する方法であって、
前記レーザ光のスポット光を楕円形とし、前記スポット光がなす前記楕円形の前記長軸の向きを調整する第4工程と;
前記長軸の向きが調整された前記レーザ光を複数の強度分布に分割することで、群状に連続する、連続したスポット光に変換する第5工程と;
前記連続したスポット光の前記群毎の中心位置が照射される前記鋼板表面上の位置を、前記板幅方向と交差する走査方向に沿って移動させる第6工程と;
前記連続したスポット光を前記鋼板表面に集光させる第7工程と;
を有し、
前記第5工程では、前記鋼板表面における前記連続したスポット光の連続する方向の向きを、前記走査方向と交差する方向に調整し、
前記第7工程では、前記鋼板表面に集光される前記連続したスポット光毎に、前記鋼板表面に前記点群溝を形成することで、前記鋼板表面に前記点列溝を形成する。
前記レーザ光のパルス周波数をFs[Hz]とし、前記鋼板表面における前記スポット光の移動速度をVs[m/s]とし、互いに隣り合う前記点群溝の前記板幅方向に沿った中心間距離をPc[μm]とし、前記点状溝の前記長軸の方向に沿った長さをdc[μm]とし、互いに隣接する前記点状溝の端部同士の前記板幅方向に沿った間隔をD[μm]とし、前記長軸が前記板幅方向に対してなす角度をθg[°]とし、前記点列方向が前記板幅方向に対してなす角度をθs[°]としたときに、下記(式16)および(式17)を満たしてもよい。
Pc=D+dc×cosθg …(式16)
Pc/cosθs=(Vs/Fs)×106…(式17)
なお、以下の説明で用いる図面は、特徴をわかりやすくするために、便宜上、特徴となる部分を拡大する等、強調して示している場合がある。
<方向性電磁鋼板の概要>
典型的な方向性電磁鋼板は、鋼板の結晶粒の磁化容易軸(体心立方晶の<100>方向)が、鋼板の圧延方向に略揃っている電磁鋼板である。方向性電磁鋼板は、圧延方向に向いた磁極を有する磁区が、磁壁を挟んで複数配列した構造を有する。このような方向性電磁鋼板は、圧延方向に磁化しやすいため、磁力線の方向がほぼ一定に流れるトランス(変圧器)の鉄芯の材料に適している。
方向性電磁鋼板は、例えば、鋼板本体(地鉄)と、鋼板本体の表裏両面に形成されたグラス被膜と、グラス被膜上に形成された絶縁被膜とを有する。鋼板本体は、例えばSiを含有する鉄合金で構成されている。
方向性電磁鋼板2は、溝形成の対象となる電磁鋼板であり、板幅Wcを有する帯状に冷間圧延されているが、図1(A)及び図2では、図示を簡略化するために、帯状の方向性電磁鋼板2を長方形状に描き、圧延方向Lに直交する方向を板幅方向Cと表示している。方向性電磁鋼板2は、図示略の搬送装置により、圧延方向Lに向かって通板される。
また、各点列溝1は、この点列溝1を構成する各点状溝1Aのなす長軸の向きGが、方向性電磁鋼板2の板幅方向Cに対してなす角が傾斜角θgとなるように形成されており、また、点列方向Sと鋼板の板幅方向Cとがなす角が走査角θsとなるように形成されている。即ち、点列溝1を構成する各点状溝1Aの長軸の向きGは、点列方向Sとは異なる方向となっている。
点状溝1Aは、例えば、図1(B)に示すように、互いに隣接する一対の点状溝1Aの、板幅方向Cに沿った間隔Dが一定となるように形成されている。また、互いに隣接する点状溝1Aの長さ方向中央部の板幅方向Cに沿った間隔Pcが一定となるように形成されている。即ち、複数の点状溝1Aが点列方向Sに沿って一定のピッチで徐々に位置をずらすように個々に平行に配置されることで、点列溝1が構成されている。また、図1(A)に示すように、点列溝1は、方向性電磁鋼板2の圧延方向Lにおいて所定のピッチPLで繰り返し複数本が形成されている。
点列溝1は、後述するようにレーザ光によって形成される。このため、図1(B)に示したように、複数の同一形状の点状溝1Aが規則的に配列された構成を有するが、レーザ光の照射状態によって全ての点状溝1Aが完全に同一な形状に形成される必要はなく、点状溝1Aの端部形状や底部形状が不揃いであり、図1(B)、1(C)に示す形状と多少異なっていてもよい。
0°<|θs|≦30° …(式2)
|θg|≦|θs| …(式3)
dL≦dc …(式6)
図1に示す方向性電磁鋼板2は、点列溝1が鋼板長手方向に間隔PLをあけて間欠的にかつ板幅方向Cと所定の走査角θsを有する走査方向Sに沿って形成されているので、機械的な耐繰り返し曲げ特性に優れる。従って、方向性電磁鋼板2をトランス用の巻鉄芯に用いるために巻回したり、折り曲げたりしたとしても、破断するおそれが少なく、クラックなどの欠陥部を生じることのない方向性電磁鋼板2を提供できる。
また、互いに隣接する個々の点状溝1Aの間に隙間が生じているため、磁束がその隙間を磁束ベクトルの方向を変えて通過できるため、磁束密度の低下代が少ない。また断面方向においても、互いに隣接する点状溝間では溝深さが浅いため、鋼板表面の磁束密度劣化代が少ない。さらに、互いに隣接する点状溝1A間の隙間は10μm~1mmと微小であり、しかもこの隙間は板幅方向Cに沿って多数個が均一に形成されているので、板幅方向Cにおいて均一な鉄損及び磁束密度が得られる。
図2は、方向性電磁鋼板2に点状溝1Aを形成するために用いる本第1実施形態のレーザ加工装置Aを示す斜視図である。
レーザ加工装置Aは、方向性電磁鋼板2の表面にパルスレーザ光を照射することで、方向性電磁鋼板2の板幅方向Cと交差する方向に延在する離散的な略楕円の形点状溝1Aからなる点列溝1を形成する装置である。
レーザ加工装置Aは、レーザ照射部3と第1光学系5と走査ミラー6と第2光学系7とを備えている。
レーザ照射部3は、レーザ出射部8と伝送ファイバ9とを備え、伝送ファイバ9は図示略のレーザ光源に接続されている。この構成により、レーザ光源にて生成されたレーザ光をレーザ出射部8に送り、レーザ出射部8からレーザ光を出射することができる。
レーザ光は、レーザ出射部8から第1光学系5を経てレーザ光10として出射された時点で、光軸に直行する断面形状が楕円形状又は線状となっている。第1光学系5は、一例として円柱レンズ、放物面レンズ、または放物面ミラーの組み合わせからなり、レーザ光の断面形状を楕円形状に変化させる機能を有する、いわゆる楕円ビームコリメータである。この楕円ビームコリメータは、レーザ光軸を中心に回転させることで、第1光学系5を経て出射されるレーザ光のスポット光のなす楕円形の長軸の向きを調整する機能を有する。
円柱レンズコリメータ11のレーザ光透過後には、走査ミラー6として利用されるポリゴンミラー12が設けられている。走査ミラー6は、ガルバノミラーであってもよい。
走査ミラー6は、第1光学系5で調整されたレーザ光を反射することでレ-ザ光の進行方向を変化させ、レーザ光のスポット光が照射される方向性電磁鋼板2上の位置を、方向性電磁鋼板2の幅方向と交差する方向である走査方向Sに沿って移動させることができる。即ち、走査角θsは、ポリゴンミラー12の走査方向で調整することができる。
また、当該スポット光の形状は、正円形状であってもよい。
第2光学系7は、走査ミラー6で反射したレーザ光10Aを透過させることで集光したパルスレーザ光10Bとしてから、方向性電磁鋼板2の表面に集光させる機能を有する。
ポリゴンミラー12は、図2に示すように、回転軸13の方向から側面視した場合に正多角形状を有した、扁平な正多角柱である。ポリゴンミラー12は、水平方向に延びた回転軸13を有しており、この回転軸13回りに回転する。
ポリゴンミラー12を回転軸13回りに回転させることで、反射面15の反射角を連続的に変更することができ、その結果、レーザ光10AはS方向に走査される。
第2光学系7は、ポリゴンミラー12からfθレンズ19に入射されたレーザ光10Aを方向性電磁鋼板2の表面にパルスレーザ光10Bとして集光して照射する。集光されたパルスレーザ光10Bは、方向性電磁鋼板2の表面を溶融及び蒸発飛散させて、方向性電磁鋼板2の表面に点状溝1Aを形成する。
第2光学系7は、方向性電磁鋼板2の表面にパルスレーザ光10Bを集光するために設けられている。パルスレーザ光10Bを方向性電磁鋼板2の表面に集光するために、円柱レンズコリメータ11とfθレンズ19との間の焦点距離や相互間隔を適宜調整することが好ましい。方向性電磁鋼板2の表面に対するパルスレーザ光10Bの走査方向Sは、上述した点列方向Sと等しく、走査方向Sは、板幅方向Cに対して走査角θsだけ傾斜する。
なお、第2光学系7に、fθレンズ19の代わりにフラットフィールドレンズを用いるようにしても、同様の機能を発揮させることが可能である。また、反射型の集光装置である放物面ミラーを用いて同様の機能を発揮させることも、可能である。
方向性電磁鋼板2は、図2の矢印L方向に一定速度で搬送されるので、パルスレーザ光10Bの走査速度とパルス時間幅、パルスとパルスの時間間隔を適宜調整することで、圧延方向L方向に一定間隔PL(図1(A)参照)で点列溝1を間欠的に連続して形成することができる。
ここで、略楕円形状をなす点状溝1Aの形成過程を説明する。図1(D)は、本実施形態における一つの略楕円形の点状溝1Aの拡大図である。また図1(E)は、当該点状溝1Aが、楕円集光されたスポット光のS方向への移動によって形成されることを説明する図である。パルスレーザのパルス時間幅がTpである場合、スポット光が速度VsでS方向に走査されると、パルス時間内にスポット光はE1からE2に移動する。その際の移動距離aは、a=Vs×Tpで求められる。
楕円スポット光は、円柱レンズコリメータ11を回転調整して、その楕円長軸方向が、板幅方向Cから角度θg2だけ傾斜させたG2方向になっている。形成される点状溝1Aの形状は、楕円スポットE1から楕円スポットE2へ移動した軌跡の最外周の形状と一致し、略楕円形状となる。この際、点状溝1Aの長軸dcの長さは、図1(E)において楕円スポットE1の下側の長軸頂点P3と、移動後の楕円スポットE2の上側頂点P2との間の距離となる。また、点状溝1Aの短軸dLはP2とP3を結ぶ直線と直交する方向の最大幅であり、点Q1と点Q2との間の距離となる。
PL=(4π/N)×f×VL/Vs×103 …(式11)
D=Pc×103-dc×cosθg …(式12)
図2に示したレーザ加工装置Aは、図1(A)~(C)に示す形状を持つ複数の点状溝1Aからなる点列溝1を形成する加工装置である。
レーザ加工装置Aにおいて、第1光学系5は、方向性電磁鋼板2の表面におけるパルスレーザ光10Bのスポット光のなす楕円形の長軸の向きGを、走査方向Sと異なる方向(好ましくは、方向性電磁鋼板2の板幅方向Cに沿う方向)に調整する。
第2光学系7は、方向性電磁鋼板2の表面に集光されるパルスレーザ光10Bのスポット光毎に、方向性電磁鋼板2の表面に点状溝1Aを形成することで、方向性電磁鋼板2の表面に点列溝1を形成する。
0°<|θs|≦30° …(式14)
|θg|≦|θs| …(式15)
dL≦dc …(式18)
次に、上述のレーザ加工装置Aにより方向性電磁鋼板2に点列溝1を加工する方向性電磁鋼板製造方法は、以下のステップを有する。
すなわち、この方向性電磁鋼板製造方法は、レーザ照射部3を用いて、レーザ光を照射するレーザ照射ステップを有する。
また、この方向性電磁鋼板製造方法は、第1光学系5を用いて、レーザ光のスポット光を楕円形に調整し、レーザ光のスポット光のなす楕円形の長軸の向きを調整する第1光学処理ステップを有する。
さらに、この方向性電磁鋼板製造方法は、走査ミラー6を用い、第1光学系5で調整されたレーザ光10を反射することで該レーザ光10の進行方向を変化させ、レーザ光10のスポット光が照射される鋼板表面上の位置を、方向性電磁鋼板2の板幅方向Cと交差する方向である走査方向Sに沿って移動させる走査処理ステップを有する。
さらに、この方向性電磁鋼板製造方法は、第2光学系7を用いて、走査ミラー6で反射したレーザ光10Aを透過し、鋼板表面に集光させる第2光学処理ステップを有する。
また、前記第2光学処理ステップでは、鋼板表面に集光されるパルスレーザ光10Bのスポット光毎に、鋼板表面に溝部を形成することで、鋼板表面に点列溝1を形成する。
以上説明の図1に示す方向性電磁鋼板2について、以下に磁区制御効果発現の原理について説明する。
図5は、板幅方向C方向から、0°を超えて傾斜して連続的に溝22を形成した従来構成を、図3及び図4と同様の視線で見た断面図である。
従って、磁区幅現象による鉄損減少と磁束密度の局所的増加による鉄損増加の差し引きにおいて、前者の方が、効果が大きいため、結果的に溝形成によって鉄損は減少する。
また、機械特性として、巻きトランス鉄芯の製造工程では板幅方向に平行な方向に変曲線を持つ折り曲げ加工が行われるが、板幅方向Cに平行(圧延方向Lに垂直)な溝は、方向性電磁鋼板の耐繰り返し曲げ加工強度を低下させ、鋼板破断のリスクが高まるため不利である。
更に、前述したように、溝は磁束の流れに対して抵抗となるため、一定磁化力で発生する磁束密度、例えばB8は低下することになる。板幅方向に傾斜して溝を形成することで若干、B8の低下は抑制される傾向があるが、連続して溝が形成される場合は大きなB8低下は避けられない。
更に、この様な点状溝1Aの配列によって、図3(A)、3(C-2)に示すように、表面、および断面からの視点では、溝間には溝が形成されない領域が発生するため、ここを磁束が流れることが可能となり、一定磁化力で発生し得る磁束密度の低下を抑制することが可能と考えた。
図6は、方向性電磁鋼板2に点状溝1Aを形成するために用いる第2実施形態のレーザ加工装置Bの概要を示す斜視図である。
レーザ加工装置Bは、方向性電磁鋼板2の表面にレーザ光を照射することで、方向性電磁鋼板2の板幅方向Cと交差する方向に延在する離散的な点列溝1を形成する装置である。
レーザ加工装置Bは、レーザ照射部3と、第1光学系5と、第2光学系25と、走査ミラー6とを備えている。
レーザ照射部3は、上記第1実施形態の構造と同様に、レーザ出射部8と伝送ファイバ9とを備える。伝送ファイバ9は、図示略のレーザ光源に接続されている。
図6では詳細を示していないが、第2光学系25を支持して第2光学系25をレーザ光10の光軸に沿って矢印26に示す前後方向に高速で移動させる移動機構27が設けられている。この移動機構27によって、第2光学系25を、走査ミラー6の動作と同期させ、レーザ光10の光路に沿って前後に移動させることで、第2光学系25を起点として、走査ミラー6の反射の後に方向性電磁鋼板2に到達すまでのレーザ光10の伝搬距離を第2光学系25の焦点距離fに一致させることができる。その結果、走査幅全体に亘り、均一な集光が得られる。
ポリゴンミラー12は、上記第1実施形態のレーザ加工装置Aの場合と同様に、第2光学系25を通過したレーザ光10Cを、方向性電磁鋼板2の表面上に対し、所定の走査方向Sに沿って走査する。
図6に示すレーザ加工装置Bによって、点列溝1を有する方向性電磁鋼板2を製造することができる。
上述のレーザ加工装置Bにより方向性電磁鋼板2に点列溝1を加工する方向性電磁鋼板製造方法は、以下のステップを有する。
すなわち、この方向性電磁鋼板製造方法は、レーザ照射部3を用いて、レーザ光10を照射するレーザ照射ステップを有する。
また、この方向性電磁鋼板製造方法は、第1光学系5を用いて、レーザ光のスポット光を楕円形に調整し、レーザ光のスポット光のなす楕円形の長軸の向きを調整する第1光学処理ステップを有する。
さらに、この方向性電磁鋼板製造方法は、移動機構27を用いてレーザ光の光軸方向に対する位置を変化させた第2光学系25を用いて、第1光学系5で調整されたレーザ光10を透過し、鋼板表面に集光させる第2光学処理ステップを有する。
さらに、この方向性電磁鋼板製造方法は、走査ミラー6を用い、第2光学系25を透過したレーザ光10Cを反射することで該レーザ光10Cの進行方向を変化させ、レーザ光10Cのスポット光が照射される鋼板表面上の位置を、方向性電磁鋼板2の板幅方向Cと交差する方向である走査方向Sに沿って移動させる走査処理ステップを有する。
方向性電磁鋼板は、成分調整された鋼片を熱延、冷延、一次再結晶・脱炭焼鈍、二次再結晶、平坦化焼鈍、表面コーティングの順番で行う製造工程を経て、最終製品となる。
深さ数十μmの点状溝は、冷延によって消失してしまう可能性が高いため、冷延工程後であれば、どの工程の時点で溝を形成しても、ほぼ同様の効果が得られる。
方向性電磁鋼板は、板幅100mm、長さ500mm、板厚0.23mmの冷延板を用いて加工を行い、異なる試験条件ごとに30枚の試験を行い、特性はこれらの平均値で評価した。
レーザ光は、パルスレーザ光を用いた。用いたパルスレーザのレーザパルス周波数は225kHzであり、パルスエネルギーは7.0mJであり、パルス時間幅Tpは0.5μsであり、スポット光形状は楕円であり、短軸径は50μmであり、長軸径は80μmに設定した。ビーム走査速度は20m/sに設定した。
以上のような高速走査では、パルス時間幅の中でレーザ光が移動するため、形成される楕円形状の点状溝の形状は、長軸方向の長さdcが、dc=90μm、短軸方向の長さdLが、dL=52μmとなる。この際の最大溝深さhは35μmであった。すなわち、発明例の方法では、レーザ光の一つのパルスで一つの点状溝を形成した。
集光したレーザ光は、板幅方向Cと交差する一方向に走査し、方向性電磁鋼板2を一定速度でL方向(圧延方向)に移動させ、その移動速度(通板速度)等を調整することで、溝部の方向性電磁鋼板2の圧延方向L(長手方向)に沿った間隔PLを、PL=3mmとした。
以上の条件で、個々の微小な楕円形状をした点状溝の長軸方向Gと板幅方向Cとの成す角である傾斜角θgを、θg=0°となるように、スポットの傾斜角θg2を適宜調整して、走査角θsを変更して鉄損W17/50の評価と、繰り返し曲げ試験による機械特性とを評価した。
比較例の方向性電磁鋼板の平均溝深さは、走査角θs=0°において最も鉄損値が低くなった約30μmとした。
なお、発明例の場合、点状溝において、方向性電磁鋼板2の横断面における微小楕円溝の深さは点状溝の長さ方向端では浅い部分が発生する。よって、平均値として連続溝と同等の溝深さを得るため、溝中心部の最大深さhは、連続溝の場合に比べ、若干深くすることが望ましい。
繰返し曲げ試験は図7(A)に示すように、方向性電磁鋼板2を治具28で固定してL方向に繰り返し曲げを行い、固定点で方向性電磁鋼板2が破断するまでの曲げ回数Nbで耐曲げ強度を評価した。曲げ回数Nbが大きい方が耐曲げ強度が高く、鉄芯を製造する際の板破断リスクが少ないことに相当する。図7(B)は折り曲げた方向性電磁鋼板2と点列溝1との配置関係を示す。
図8より、従来形状の連続溝では、走査角θsを増大させることで鉄損低減効果は減少するため、鉄損値(W17/50)は、走査角θsの増加に伴い増加する。
一方、発明例に係る方向性電磁鋼板では、個々の溝部の方向が板幅方向Cにほぼ平行(L方向にほぼ直交)であるため、鉄損値(W17/50)は従来の連続溝の場合よりも小さく、走査角θs=30°程度までは鉄損値(W17/50)の増加がほとんどなかった。
走査角θs>30°では、斜めに配列された微小楕円溝間の隙間が過剰に増加するため、鉄損改善の源である磁束の障壁効果が減少して、鉄損が増加したと考えられる。よって発明例において、走査角θsが比較的大きくても比較例よりも良好な鉄損が得られ、特に走査角θsが30°以下であることがより好ましいことが分かった。
発明例における曲げ回数Nbは、従来技術の方向性電磁鋼板の場合とほぼ同様に走査角θsの増加に伴って増加しており、走査角θsが0°より大きい場合においてNbが大きく増加することが分かった。
従って、図8、9に示す結果より、発明例の方向性電磁鋼板は、低い鉄損と十分な耐繰り返し曲げ加工性を両立できることが分かった。
図10と図11は、走査角θsを10°又は30°に設定した場合に、点状溝の傾斜角θgを走査角θsと同方向で角度変更した際の鉄損値(W17/50)を示す。その他の条件は実施例1と同じである。
傾斜角θgが0°より増加することで磁束の障壁効果は減少するため、鉄損値(W17/50)は微増に留まるが、10°を越えると鉄損値(W17/50)の増加が顕著となるため、傾斜角θgは10°以下に調整することが好ましいことが分かった。
点状溝の板幅方向Cに沿う重畳度合いを表す間隔D(隣接する点状溝の板幅方向Cに沿った間隔)と、鉄損値(W17/50)との関係を評価した。間隔Dは、図1(B)に図示されており、間隔Dがプラスであれば、互いに隣接する点状溝の端部どうしが板幅方向Cに沿って離れており、間隔Dがマイナスであれば、互いに隣接する点状溝の端部どうしが重なっていることを示す。
図12は、重畳度合いを表すDと、点状溝の長軸径dcとの比で代表し、鉄損値(W17/50)への影響を調べた結果である。θs=10°、θg=0°であり、レーザ光の走査速度、パルス時間幅Tpを一定として、パルスの周波数Fpを変更することで中心間距離Pcを制御して間隔Dを調整した。その他の条件は実施例1に同じである。
一方、重畳度合いを表す間隔Dの値がマイナスとなり、重畳幅が増加する場合、鉄損値(W17/50)の増加は比較的抑えられる。W17/50は、50Hzの交流磁界によって最大磁束密度が強制的1.7Tになるように磁化した場合の鉄損である。そこで、表面に溝が大量に形成されると、図3(C-2)、図4(C-2)、図5(C-2)で示したように、溝下部ではL方向断面積が減り、磁束密度が局所的に増加する。鉄損は磁束密度の2乗に比例するため、すなわち局所的に鉄損値が増加するためである。よって、間隔Dの値をマイナス側の過剰な値とすることは好ましくない。したがって、D/dcの範囲を-0.3以上、0.2以下の範囲とすることが好ましいことが分かった。
図16は、発明例である実施例4の説明図であり、電磁鋼板の実製造ラインでコイル状に連続で製造する場合を想定して、実コイル幅に相当する板幅Wc=1000mmの鋼板に対して、点列溝を幅方向で複数に分割して溝を形成した場合である。本実施例は、互いに隣接する点列溝44Aの重畳幅Daの影響を示す実施例である。
図18及び表1は鉄損、曲げ特性、磁束密度に関して、溝加工前の方向性電磁鋼板の特性を基準にして、従来技術と発明例とを比較した説明図と比較結果である。冷延後の方向性電磁鋼板を用意して、上記実施例1に記載した方法と同様の方法でこれらの溝パターンによる特性を比較評価した。
また、溝幅dLが300μmを超えると母材の除去体積の増加が顕著になり、磁束の発生自体を阻害してしまうため、高い磁束密度が要求される方向性電磁鋼板の場合には好ましくない。よって、短軸径dLの範囲は10μm~300μmがより好ましい。
なお、長軸径dcは溝幅dLより長くすればよいが、例えば長軸径dcが30000μm、すなわち30mmを越えると、板幅を100mm程度に切断してトランス鉄芯を製造する場合には、その幅内に含まれる点状溝の数が3~4か所と少なくなる。点状溝と溝の間は磁束の流れが他とは異なり、磁束が集中しやすく、この様な箇所が数か所しかない場合は、板としての磁気特性が不均一になる可能性がある、そのため、長軸径dcは、最大で30mm程度が好ましい。
図13は、方向性電磁鋼板2に点群溝33Aを形成するために用いる第3実施形態のレーザ加工装置Eの概要を示す斜視図である。
レーザ加工装置Eは、方向性電磁鋼板2の表面にレーザ光を照射することで、図14に示すように、方向性電磁鋼板2の板幅方向Cと交差する方向に延在する点列溝33を形成する装置である。
図14に、点群溝33Aを間欠的に複数形成した点列溝33を示す。本実施形態の点群溝33Aは、複数の楕円穴33aを平面視で数珠繋ぎ(daisy chain)に点群状に接続した、連続した溝部(楕円穴33a)からなる形状を有する。各楕円穴33aは、内面33bと底面33cを有する1つの穴であるが、互いに隣接する楕円穴33aの長軸側の内面どうしを一部重ね合わせて複数の楕円穴33aが走査方向Sに沿って数珠繋ぎに点群状に連結され、1つの点群溝33Aが形成されている。
即ち、点群溝33Aが走査方向Sに沿って間欠的に所定のピッチで整列形成されていること、板幅方向Cに対して、点群溝33Aの長軸の傾斜角θgが規定されること、同じく走査角θsが規定されること、点群溝33Aの長軸方向の長さdcが規定されること、点群溝33Aの短軸長さdcが規定されることも、図1に示した点状溝1Aと同等である。また、点群溝33Aの集合体である点列溝33が方向性電磁鋼板2の長手方向に所定の間隔PLをあけて整列して形成されていることも、先の点列溝1と同等である。また、点群状に集光されたスポット光がパルス時間Tpの間に速度Vsで移動して形成された溝形状であることも同等である。
レーザ照射部3は、上記第1実施形態の構造と同様に、レーザ出射部8と伝送ファイバ9を備え、伝送ファイバ9が図示略のレーザ光源に接続されている。
レーザ照射部3の出射側に配置されている第1光学系5は、先のレーザ加工装置Aと同様に円柱レンズコリメータ11からなる。
第3光学系35は、上記第1実施形態の構造と第2光学系7と同様に、fθレンズ(スキャンレンズ)19を備えている。
ビーム強度分布変換素子34は、レーザ光の回折、透過によって強度分布を変換又は分割する素子であり、fθレンズと組み合わせて集光点(方向性電磁鋼板2の表面)での強度分布を群状にすることができる。
ここで、方向性電磁鋼板2の鋼板表面に集光照射されるレーザ光10Fは、図13(C)に示すように6つの連なる強度分布を有する空間強度分布を示すため、先の実施形態で形成した点状溝1Aの代わりに、6つの楕円穴33aが数珠繋ぎ状に連結した点群溝33Aを形成できる。
図13(A)に示すレーザ加工装置Eにおいて、ビーム強度分布変換素子34に入射するべきレーザ光は、例えば、中心強度が高く、端で低い単一ピークを有するガウシアン分布のレーザ光を用いることができる。また、図13(B)に示すようにフラットトップモードの分布を有するレーザ光を用いても良い。
上述のレーザ加工装置Eにより方向性電磁鋼板2に点列溝1を加工する方向性電磁鋼板製造方法は、以下のステップを有する。
すなわち、この方向性電磁鋼板製造方法は、レーザ照射部3を用いて、レーザ光10を照射するレーザ照射ステップを有する。
また、この方向性電磁鋼板製造方法は、第1光学系5を用いて、レーザ光10のスポット光を楕円形に調整し、レーザ光10のスポット光のなす楕円形の長軸の向きを調整する第1光学処理ステップを有する。
さらに、この方向性電磁鋼板製造方法は、レーザ光10を透過し、レーザ光10の空間強度分布を二つ以上の連なる複数の強度分布にビーム強度分布変換素子34を用いて調整するレーザ分割ステップを有する。
さらに、この方向性電磁鋼板製造方法は、走査ミラー6を用い、ビーム分割素子34で調整されたレーザ光10を反射することでレーザ光10の進行方向を変化させ、レーザ光10のスポット光が照射される鋼板上の位置を、方向性電磁鋼板2の板幅方向と交差する方向である走査方向Sに沿って移動させる走査処理ステップを有する。
さらに、この方向性電磁鋼板製造方法は、第3光学系35を用いて、走査ミラー6で反射したレーザ光を透過し、鋼板の表面に集光させる第3光学処理ステップを有する。
(1)すなわち、本発明の一態様に係る方向性電磁鋼板は、
鋼板表面に沿って、圧延方向と、前記圧延方向に直交する板幅方向とを有する方向性電磁鋼板であって、
前記圧延方向が、前記方向性電磁鋼板の磁化容易方向と一致しており、
前記鋼板表面に、前記板幅方向と交差する点列方向に沿って延在する点列溝を有し、
前記点列溝が、略楕円形の点状溝、または、複数の穴が直線的に連なって形成された点群溝が、複数、直線的に並んで構成され、
前記点状溝または前記点群溝の長軸が、前記点列方向に対して交差している。
前記長軸が前記板幅方向に対してなす角度をθg[°]とし、前記点列方向が前記板幅方向に対してなす角度をθs[°]としたときに、下記(式1)~(式3)を満たしてもよい。
0°≦|θg|≦10° …(式1)
0°<|θs|≦30° …(式2)
|θg|≦|θs| …(式3)
前記点列溝が、前記複数の点状溝で構成され;
前記点状溝の前記長軸の方向に沿った長さをdc[μm]とし、互いに隣接する前記点状溝の端部同士の前記板幅方向に沿った間隔をD[μm]としたときに、下記(式4)を満たす。
-0.3≦(D/dc)≦0.2 …(式4)
ここで、前記間隔D[μm]は、前記圧延方向に沿って見た視線において、前記端部同士間が互いに重なっていない場合を正の値とし、前記端部同士間が一点で接している場合を0[μm]とし、前記端部同士間が互いに重なっている場合を負の値とする。
前記点列溝が、前記複数の点状溝で構成され;
前記点状溝の前記長軸の方向に沿った長さをdc[μm]とし、前記長軸に直交する方向を前記点状溝の短軸方向とし、前記点状溝の前記短軸方向に沿った長さをdL[μm]としたときに、下記(式5)及び(式6)を満たす。なお、長さdc[μm]の最大値を30000μmとしてもよい。
10μm≦dL≦300μm …(式5)
dL≦dc …(式6)
前記点列溝が、前記複数の点状溝で構成され;
前記点状溝の最大深さをh[μm]としたときに、下記(式7)を満たす。
5μm≦h≦100μm …(式7)
前記鋼板表面上に、前記点列溝が複数本、前記圧延方向に等間隔で形成され;
互いに隣接する前記点列溝の前記圧延方向に沿った間隔をPL[mm]としたときに、下記(式8)を満たす。
1mm≦PL≦10mm ・・・(式8)
前記点列溝が前記板幅方向で2つ以上に分割されており、分割位置において互いに隣接する前記点列溝の端部間の前記板幅方向に沿った間隔をDa[mm]としたときに、下記(式9)を満たす。
-10mm≦Da≦2mm …(式9)
ここで、前記間隔Da[mm]は、前記圧延方向に沿って見た視線において、前記端部同士間が互いに重なっていない場合を正の値とし、前記端部同士間が一点で接している場合を0[μm]とし、前記端部同士間が互いに重なっている場合を負の値とする。
前記鋼板表面にレーザ光を照射することによって前記点状溝で構成された前記点列溝を形成して上記(1)~(7)のいずれか一項に記載の方向性電磁鋼板を製造する装置であって、
前記レーザ光を照射するレーザ照射部と;
前記レーザ光のスポット光を楕円形とし、前記スポット光のなす前記楕円形の前記長軸の向きを調整する第1光学系と;
前記第1光学系で調整された前記レーザ光を反射することで進行方向を変化させ、前記スポット光が照射される前記鋼板表面上の位置を、前記板幅方向と交差する走査方向に沿って移動させる走査ミラーと;
前記走査ミラーで反射した前記レーザ光を透過または反射し、前記鋼板表面に集光させる第2光学系と;
を有し、
前記第1光学系は、前記鋼板表面における前記スポット光がなす前記楕円形の前記長軸の向きを、前記走査方向と交差する方向に調整し、
前記第2光学系で前記鋼板表面に集光される前記スポット光毎に、前記鋼板表面に前記点状溝を形成することで、前記鋼板表面に前記点列溝を形成し、
前記レーザ光のパルス周波数をFs[Hz]とし、前記鋼板表面における前記スポット光の移動速度をVs[m/s]とし、互いに隣り合う前記点状溝の前記板幅方向に沿った中心間距離をPc[μm]とし、前記点状溝の前記長軸の方向に沿った長さをdc[μm]とし、互いに隣接する前記点状溝の端部同士の前記板幅方向に沿った間隔をD[μm]とし、前記長軸が前記板幅方向に対してなす角度をθg[°]とし、前記点列方向が前記板幅方向に対してなす角度をθs[°]としたときに、下記(式10)および(式11)を満たす。
Pc=D+dc×cosθg …(式10)
Pc/cosθs=(Vs/Fs)×106…(式11)
前記鋼板表面にレーザ光を照射することによって前記点状溝で構成された前記点列溝を形成して上記(1)~(7)のいずれか一項に記載の方向性電磁鋼板を製造する装置であって、
前記レーザ光を照射するレーザ照射部と;
前記レーザ光のスポット光を楕円形とし、前記スポット光がなす前記楕円形の前記長軸の向きを調整する第1光学系と;
前記第1光学系で調整された前記レーザ光を透過し、前記鋼板表面に集光させる第2光学系と;
前記第2光学系を透過した前記レーザ光を反射することで進行方向を変化させ、前記スポット光が照射される前記鋼板表面上の位置を、前記板幅方向と交差する走査方向に沿って移動させる走査ミラーと;
を有し、
前記第1光学系は、前記鋼板表面における前記スポット光がなす前記楕円形の前記長軸の向きを、前記走査方向と交差する方向に調整し、
前記第2光学系で前記鋼板表面に集光される前記スポット光毎に、前記鋼板表面に前記点状溝を形成することで、前記鋼板表面に前記点列溝を形成し、
前記レーザ光のパルス周波数をFs[Hz]とし、前記鋼板表面における前記スポット光の移動速度をVs[m/s]とし、互いに隣り合う前記点状溝の前記板幅方向に沿った中心間距離をPc[μm]とし、前記点状溝の前記長軸の方向に沿った長さをdc[μm]とし、互いに隣接する前記点状溝の端部同士の前記板幅方向に沿った間隔をD[μm]とし、前記長軸が前記板幅方向に対してなす角度をθg[°]とし、前記点列方向が前記板幅方向に対してなす角度をθs[°]としたときに、下記(式12)および(式13)を満たす。
Pc=D+dc×cosθg …(式12)
Pc/cosθs=(Vs/Fs)×106…(式13)
前記鋼板表面にレーザ光を照射することによって前記点群溝で構成された前記点列溝を形成して上記(1)または(2)に記載の方向性電磁鋼板を製造する装置であって、
前記レーザ光を照射するレーザ照射部と;
前記レーザ光のスポット光を楕円形とし、前記スポット光がなす前記楕円形の前記長軸の向きを調整する第1光学系と;
前記第1光学系で調整された前記レーザ光を透過し、前記レーザ光を複数の強度分布に分割することで、群状に連続する、連続したスポット光に変換するビーム強度分布変換素子と;
前記ビーム強度分布変換素子で変換された前記連続したスポット光を反射することで進行方向を変化させ、前記連続したスポット光の群毎の中心位置が照射される前記鋼板表面上の位置を、前記板幅方向と交差する走査方向に沿って移動させる走査ミラーと;
前記走査ミラーで反射した前記連続したスポット光を透過し、前記鋼板表面に集光させる第3光学系と;
を有し、
前記第1光学系は、前記鋼板表面における前記連続したスポット光の連続する方向の向きを、前記走査方向と交差する方向に調整し、
前記第3光学系で前記鋼板表面に集光される前記連続したスポット光毎に、前記鋼板表面に前記点群溝を形成することで、前記鋼板表面に前記点列溝を形成し、
前記レーザ光のパルス周波数をFs[Hz]とし、前記鋼板表面における前記スポット光の移動速度をVs[m/s]とし、互いに隣り合う前記点群溝の前記板幅方向に沿った中心間距離をPc[μm]とし、前記点状溝の前記長軸の方向に沿った長さをdc[μm]とし、互いに隣接する前記点状溝の端部同士の前記板幅方向に沿った間隔をD[μm]とし、前記長軸が前記板幅方向に対してなす角度をθg[°]とし、前記点列方向が前記板幅方向に対してなす角度をθs[°]としたときに、下記(式14)および(式15)を満たす。
Pc=D+dc×cosθg …(式14)
Pc/cosθs=(Vs/Fs)×106…(式15)
前記鋼板表面にレーザ光を照射することによって前記点状溝で構成された前記点列溝を形成して上記(1)~(7)のいずれか一項に記載の方向性電磁鋼板を製造する方法であって、
前記レーザ光のスポット光を楕円形とし、前記スポット光がなす前記楕円形の前記長軸の向きを調整する第1工程と;
前記長軸の向きが調整された前記レーザ光の進行方向を変化させ、前記スポット光が照射される前記鋼板表面上の位置を、前記板幅方向と交差する走査方向に沿って移動させる第2工程と;
前記スポット光を前記鋼板表面に集光させる第3工程と;
を有し、
前記第1工程では、前記鋼板表面における前記スポット光がなす前記楕円形の前記長軸の向きを、前記走査方向と交差する方向に調整し、
前記第3工程では、前記鋼板表面に集光される前記スポット光毎に、前記鋼板表面に前記点状溝を形成することで、前記鋼板表面に前記点列溝を形成する。
前記鋼板表面にレーザ光を照射することによって前記点群溝で構成された前記点列溝を形成して請求項1または2に記載の方向性電磁鋼板を製造する方法であって、
前記レーザ光のスポット光を楕円形とし、前記スポット光がなす前記楕円形の前記長軸の向きを調整する第4工程と;
前記長軸の向きが調整された前記レーザ光を複数の強度分布に分割することで、群状に連続する、連続したスポット光に変換する第5工程と;
前記連続したスポット光の前記群毎の中心位置が照射される前記鋼板表面上の位置を、前記板幅方向と交差する走査方向に沿って移動させる第6工程と;
前記連続したスポット光を前記鋼板表面に集光させる第7工程と;
を有し、
前記第5工程では、前記鋼板表面における前記連続したスポット光の連続する方向の向きを、前記走査方向と交差する方向に調整し、
前記第7工程では、前記鋼板表面に集光される前記連続したスポット光毎に、前記鋼板表面に前記点群溝を形成することで、前記鋼板表面に前記点列溝を形成する。
前記レーザ光のパルス周波数をFs[Hz]とし、前記鋼板表面における前記スポット光の移動速度をVs[m/s]とし、互いに隣り合う前記点群溝の前記板幅方向に沿った中心間距離をPc[μm]とし、前記点状溝の前記長軸の方向に沿った長さをdc[μm]とし、互いに隣接する前記点状溝の端部同士の前記板幅方向に沿った間隔をD[μm]とし、前記長軸が前記板幅方向に対してなす角度をθg[°]とし、前記点列方向が前記板幅方向に対してなす角度をθs[°]としたときに、下記(式16)および(式17)を満たしてもよい。
Pc=D+dc×cosθg …(式16)
Pc/cosθs=(Vs/Fs)×106…(式17)
Claims (14)
- 鋼板表面に沿って、圧延方向と、前記圧延方向に直交する板幅方向とを有する方向性電磁鋼板であって、
前記圧延方向が、前記方向性電磁鋼板の磁化容易方向と一致しており、
前記鋼板表面に、前記板幅方向と交差する点列方向に沿って延在する点列溝を有し、
前記点列溝が、略楕円形の点状溝、または、複数の穴が直線的に連なって形成された点群溝が、複数、直線的に並んで構成され、
前記点状溝または前記点群溝の長軸が、前記点列方向に対して交差している
ことを特徴とする方向性電磁鋼板。 - 前記長軸が前記板幅方向に対してなす角度をθg[°]とし、前記点列方向が前記板幅方向に対してなす角度をθs[°]としたときに、下記(式1)~(式3)を満たす
ことを特徴とする請求項1に記載の方向性電磁鋼板。
0°≦|θg|≦10° …(式1)
0°<|θs|≦30° …(式2)
|θg|≦|θs| …(式3) - 前記点列溝が、前記複数の点状溝で構成され;
前記点状溝の前記長軸の方向に沿った長さをdc[μm]とし、互いに隣接する前記点状溝の端部同士の前記板幅方向に沿った間隔をD[μm]としたときに、下記(式4)を満たす;
ことを特徴とする請求項1又は2に記載の方向性電磁鋼板。
-0.3≦(D/dc)≦0.2 …(式4)
ここで、前記間隔D[μm]は、前記圧延方向に沿って見た視線において、前記端部同士間が互いに重なっていない場合を正の値とし、前記端部同士間が一点で接している場合を0[μm]とし、前記端部同士間が互いに重なっている場合を負の値とする。 - 前記点列溝が、前記複数の点状溝で構成され;
前記点状溝の前記長軸の方向に沿った長さをdc[μm]とし、前記長軸に直交する方向を前記点状溝の短軸方向とし、前記点状溝の前記短軸方向に沿った長さをdL[μm]としたときに、下記(式5)及び(式6)を満たす;
ことを特徴とする請求項1に記載の方向性電磁鋼板。
10μm≦dL≦300μm …(式5)
dL≦dc …(式6) - 前記点列溝が、前記複数の点状溝で構成され;
前記点状溝の最大深さをh[μm]としたときに、下記(式7)を満たす
ことを特徴とする請求項1に記載の方向性電磁鋼板。
5μm≦h≦100μm …(式7) - 前記鋼板表面上に、前記点列溝が複数本、前記圧延方向に等間隔で形成され;
互いに隣接する前記点列溝の前記圧延方向に沿った間隔をPL[mm]としたときに、下記(式8)を満たす;
ことを特徴とする請求項1に記載の方向性電磁鋼板。
1mm≦PL≦10mm ・・・(式8) - 前記点列溝が前記板幅方向で2つ以上に分割されており、分割位置において互いに隣接する前記点列溝の端部間の前記板幅方向に沿った間隔をDa[mm]としたときに、下記(式9)を満たす
ことを特徴とする請求項1に記載の方向性電磁鋼板。
-10mm≦Da≦2mm …(式9)
ここで、前記間隔Da[mm]は、前記圧延方向に沿って見た視線において、前記端部同士間が互いに重なっていない場合を正の値とし、前記端部同士間が一点で接している場合を0[μm]とし、前記端部同士間が互いに重なっている場合を負の値とする。 - 前記鋼板表面にレーザ光を照射することによって前記点状溝で構成された前記点列溝を形成して請求項1~7のいずれか一項に記載の方向性電磁鋼板を製造する装置であって、
前記レーザ光を照射するレーザ照射部と;
前記レーザ光のスポット光を楕円形とし、前記スポット光のなす前記楕円形の前記長軸の向きを調整する第1光学系と;
前記第1光学系で調整された前記レーザ光を反射することで進行方向を変化させ、前記スポット光が照射される前記鋼板表面上の位置を、前記板幅方向と交差する走査方向に沿って移動させる走査ミラーと;
前記走査ミラーで反射した前記レーザ光を透過または反射し、前記鋼板表面に集光させる第2光学系と;
を有し、
前記第1光学系は、前記鋼板表面における前記スポット光がなす前記楕円形の前記長軸の向きを、前記走査方向と交差する方向に調整し、
前記第2光学系で前記鋼板表面に集光される前記スポット光毎に、前記鋼板表面に前記点状溝を形成することで、前記鋼板表面に前記点列溝を形成し、
前記レーザ光のパルス周波数をFs[Hz]とし、前記鋼板表面における前記スポット光の移動速度をVs[m/s]とし、互いに隣り合う前記点状溝の前記板幅方向に沿った中心間距離をPc[μm]とし、前記点状溝の前記長軸の方向に沿った長さをdc[μm]とし、互いに隣接する前記点状溝の端部同士の前記板幅方向に沿った間隔をD[μm]とし、前記長軸が前記板幅方向に対してなす角度をθg[°]とし、前記点列方向が前記板幅方向に対してなす角度をθs[°]としたときに、下記(式10)および(式11)を満たす
ことを特徴とする方向性電磁鋼板製造装置。
Pc=D+dc×cosθg …(式10)
Pc/cosθs=(Vs/Fs)×106…(式11) - 前記鋼板表面にレーザ光を照射することによって前記点状溝で構成された前記点列溝を形成して請求項1~7のいずれか一項に記載の方向性電磁鋼板を製造する装置であって、
前記レーザ光を照射するレーザ照射部と;
前記レーザ光のスポット光を楕円形とし、前記スポット光がなす前記楕円形の前記長軸の向きを調整する第1光学系と;
前記第1光学系で調整された前記レーザ光を透過し、前記鋼板表面に集光させる第2光学系と;
前記第2光学系を透過した前記レーザ光を反射することで進行方向を変化させ、前記スポット光が照射される前記鋼板表面上の位置を、前記板幅方向と交差する走査方向に沿って移動させる走査ミラーと;
を有し、
前記第1光学系は、前記鋼板表面における前記スポット光がなす前記楕円形の前記長軸の向きを、前記走査方向と交差する方向に調整し、
前記第2光学系で前記鋼板表面に集光される前記スポット光毎に、前記鋼板表面に前記点状溝を形成することで、前記鋼板表面に前記点列溝を形成し、
前記レーザ光のパルス周波数をFs[Hz]とし、前記鋼板表面における前記スポット光の移動速度をVs[m/s]とし、互いに隣り合う前記点状溝の前記板幅方向に沿った中心間距離をPc[μm]とし、前記点状溝の前記長軸の方向に沿った長さをdc[μm]とし、互いに隣接する前記点状溝の端部同士の前記板幅方向に沿った間隔をD[μm]とし、前記長軸が前記板幅方向に対してなす角度をθg[°]とし、前記点列方向が前記板幅方向に対してなす角度をθs[°]としたときに、下記(式12)および(式13)を満たす
ことを特徴とする方向性電磁鋼板製造装置。
Pc=D+dc×cosθg …(式12)
Pc/cosθs=(Vs/Fs)×106…(式13) - 前記鋼板表面にレーザ光を照射することによって前記点群溝で構成された前記点列溝を形成して請求項1または2に記載の方向性電磁鋼板を製造する装置であって、
前記レーザ光を照射するレーザ照射部と;
前記レーザ光のスポット光を楕円形とし、前記スポット光がなす前記楕円形の前記長軸の向きを調整する第1光学系と;
前記第1光学系で調整された前記レーザ光を透過し、前記レーザ光を複数の強度分布に分割することで、群状に連続する、連続したスポット光に変換するビーム強度分布変換素子と;
前記ビーム強度分布変換素子で変換された前記連続したスポット光を反射することで進行方向を変化させ、前記連続したスポット光の群毎の中心位置が照射される前記鋼板表面上の位置を、前記板幅方向と交差する走査方向に沿って移動させる走査ミラーと;
前記走査ミラーで反射した前記連続したスポット光を透過し、前記鋼板表面に集光させる第3光学系と;
を有し、
前記第1光学系は、前記鋼板表面における前記連続したスポット光の連続する方向の向きを、前記走査方向と交差する方向に調整し、
前記第3光学系で前記鋼板表面に集光される前記連続したスポット光毎に、前記鋼板表面に前記点群溝を形成することで、前記鋼板表面に前記点列溝を形成し、
前記レーザ光のパルス周波数をFs[Hz]とし、前記鋼板表面における前記スポット光の移動速度をVs[m/s]とし、互いに隣り合う前記点群溝の前記板幅方向に沿った中心間距離をPc[μm]とし、前記点状溝の前記長軸の方向に沿った長さをdc[μm]とし、互いに隣接する前記点状溝の端部同士の前記板幅方向に沿った間隔をD[μm]とし、前記長軸が前記板幅方向に対してなす角度をθg[°]とし、前記点列方向が前記板幅方向に対してなす角度をθs[°]としたときに、下記(式14)および(式15)を満たす
ことを特徴とする方向性電磁鋼板製造方法。
Pc=D+dc×cosθg …(式14)
Pc/cosθs=(Vs/Fs)×106…(式15) - 前記鋼板表面にレーザ光を照射することによって前記点状溝で構成された前記点列溝を形成して請求項1~7のいずれか一項に記載の方向性電磁鋼板を製造する方法であって、
前記レーザ光のスポット光を楕円形とし、前記スポット光がなす前記楕円形の前記長軸の向きを調整する第1工程と;
前記長軸の向きが調整された前記レーザ光の進行方向を変化させ、前記スポット光が照射される前記鋼板表面上の位置を、前記板幅方向と交差する走査方向に沿って移動させる第2工程と;
前記スポット光を前記鋼板表面に集光させる第3工程と;
を有し、
前記第1工程では、前記鋼板表面における前記スポット光がなす前記楕円形の前記長軸の向きを、前記走査方向と交差する方向に調整し、
前記第3工程では、前記鋼板表面に集光される前記スポット光毎に、前記鋼板表面に前記点状溝を形成することで、前記鋼板表面に前記点列溝を形成する
ことを特徴とする方向性電磁鋼板製造方法。 - 前記レーザ光のパルス周波数をFs[Hz]とし、前記鋼板表面における前記スポット光の移動速度をVs[m/s]とし、互いに隣り合う前記点群溝の前記板幅方向に沿った中心間距離をPc[μm]とし、前記点状溝の前記長軸の方向に沿った長さをdc[μm]とし、互いに隣接する前記点状溝の端部同士の前記板幅方向に沿った間隔をD[μm]とし、前記長軸が前記板幅方向に対してなす角度をθg[°]とし、前記点列方向が前記板幅方向に対してなす角度をθs[°]としたときに、下記(式16)および(式17)を満たす
ことを特徴とする請求項11に記載の方向性電磁鋼板製造方法。
Pc=D+dc×cosθg …(式16)
Pc/cosθs=(Vs/Fs)×106…(式17) - 前記鋼板表面にレーザ光を照射することによって前記点群溝で構成された前記点列溝を形成して請求項1または2に記載の方向性電磁鋼板を製造する方法であって、
前記レーザ光のスポット光を楕円形とし、前記スポット光がなす前記楕円形の前記長軸の向きを調整する第4工程と;
前記長軸の向きが調整された前記レーザ光を複数の強度分布に分割することで、群状に連続する、連続したスポット光に変換する第5工程と;
前記連続したスポット光の前記群毎の中心位置が照射される前記鋼板表面上の位置を、前記板幅方向と交差する走査方向に沿って移動させる第6工程と;
前記連続したスポット光を前記鋼板表面に集光させる第7工程と;
を有し、
前記第5工程では、前記鋼板表面における前記連続したスポット光の連続する方向の向きを、前記走査方向と交差する方向に調整し、
前記第7工程では、前記鋼板表面に集光される前記連続したスポット光毎に、前記鋼板表面に前記点群溝を形成することで、前記鋼板表面に前記点列溝を形成する
ことを特徴とする方向性電磁鋼板製造方法。 - 前記レーザ光のパルス周波数をFs[Hz]とし、前記鋼板表面における前記スポット光の移動速度をVs[m/s]とし、互いに隣り合う前記点群溝の前記板幅方向に沿った中心間距離をPc[μm]とし、前記点状溝の前記長軸の方向に沿った長さをdc[μm]とし、互いに隣接する前記点状溝の端部同士の前記板幅方向に沿った間隔をD[μm]とし、前記長軸が前記板幅方向に対してなす角度をθg[°]とし、前記点列方向が前記板幅方向に対してなす角度をθs[°]としたときに、下記(式16)および(式17)を満たす
ことを特徴とする請求項13に記載の方向性電磁鋼板製造方法。
Pc=D+dc×cosθg …(式16)
Pc/cosθs=(Vs/Fs)×106…(式17)
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WO1997024466A1 (fr) | 1995-12-27 | 1997-07-10 | Nippon Steel Corporation | Tole d'acier magnetique ayant d'excellentes proprietes magnetiques, et son procede de fabrication |
JP2006233299A (ja) * | 2005-02-25 | 2006-09-07 | Nippon Steel Corp | 磁気特性の優れた一方向性電磁鋼板およびその製造方法 |
WO2012164702A1 (ja) * | 2011-06-01 | 2012-12-06 | 新日鐵住金株式会社 | 方向性電磁鋼板の製造装置及び方向性電磁鋼板の製造方法 |
WO2016171129A1 (ja) | 2015-04-20 | 2016-10-27 | 新日鐵住金株式会社 | 方向性電磁鋼板 |
WO2016171130A1 (ja) | 2015-04-20 | 2016-10-27 | 新日鐵住金株式会社 | 方向性電磁鋼板 |
JP2017125250A (ja) * | 2016-01-15 | 2017-07-20 | 新日鐵住金株式会社 | 方向性電磁鋼板製造方法、方向性電磁鋼板製造装置、及び方向性電磁鋼板 |
WO2017171013A1 (ja) | 2016-03-31 | 2017-10-05 | 新日鐵住金株式会社 | 方向性電磁鋼板 |
JP2019137883A (ja) * | 2018-02-08 | 2019-08-22 | 日本製鉄株式会社 | 方向性電磁鋼板、および方向性電磁鋼板の製造方法 |
JP2022007442A (ja) | 2020-06-26 | 2022-01-13 | 株式会社豊田自動織機 | 排気浄化装置 |
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