ELECTRICAL STEEL SHEET WITH ORIENTED GRAIN STRUCTURE AND A METHOD FOR ITS MANUFACTURING

Claims

1. A sheet of grain-oriented electrical steel containing: a plurality of processing lines for controlling magnetic domains running in a direction intersecting the rolling direction on the surface, in this case: in the case where a square evaluation area having a side length of 50 mm and a side parallel to the rolling direction is specified on the surface, and in addition, imaginary lines parallel to the rolling direction and having a length of 50 mm are specified in the evaluation area at intervals of 5 mm in the direction perpendicular to the rolling direction, and on at least one of the imaginary lines, of the plurality of intersection points of the imaginary line and the plurality of processing lines for controlling magnetic domains, the absolute maximum value of the interval between adjacent intersection points in the rolling direction is more than 20 mm, and the average value of the distances between the magnetic domain walls measured along the imaginary line is 600 μm or less.

2. A sheet of electrical steel with an oriented grain structure according to paragraph 1, in which: the average value of the distances between magnetic domain walls, measured along the imaginary line, is 500 µm or less.

3. A sheet of electrical steel with an oriented grain structure according to paragraph 1, in which: the average value of the distances between magnetic domain walls measured along an imaginary line is 600 µm or less on each of two or more imaginary lines for which the absolute maximum value of said intervals in the rolling direction is more than 20 mm.

4. A sheet of electrical steel with an oriented grain structure according to paragraph 3, in which: the average value of the distances between magnetic domain walls measured along an imaginary line is 500 µm or less on each of two or more imaginary lines for which the absolute maximum value of said intervals in the rolling direction is more than 20 mm.

5. A sheet of electrical steel with an oriented grain structure according to paragraph 1, in which: the absolute maximum value of the said interval in the rolling direction is more than 30 mm.

6. A sheet of electrical steel with an oriented grain structure, containing: a plurality of processing lines for controlling magnetic domains running in a direction intersecting the rolling direction on the surface, in this case: in the case where a square evaluation area having a side length of 50 mm and a side parallel to the rolling direction is specified on the surface, and in addition, imaginary lines parallel to the rolling direction and having a length of 50 mm are specified in the evaluation area at intervals of 5 mm in the direction perpendicular to the rolling direction, on at least one of the imaginary lines, of the plurality of intersection points of the imaginary line and the plurality of processing lines for controlling magnetic domains, the absolute maximum value of the interval between adjacent intersection points in the rolling direction is more than 20 mm, and the absolute maximum value of the distance between the magnetic domain walls, measured along the imaginary line, is 1200 μm or less.

7. A sheet of electrical steel with an oriented grain structure according to paragraph 6, in which: the absolute maximum value of the distances between magnetic domain walls, measured along the imaginary line, is 800 µm or less.

8. A sheet of electrical steel with an oriented grain structure according to paragraph 6, in which: the absolute maximum value of the distances between magnetic domain walls measured along an imaginary line is 1200 µm or less on each of two or more imaginary lines for which the absolute maximum value of said interval in the rolling direction is more than 20 mm.

9. A sheet of electrical steel with an oriented grain structure according to paragraph 6, in which: the absolute maximum value of the distances between magnetic domain walls measured along an imaginary line is 800 µm or less on each of two or more imaginary lines for which the absolute maximum value of said interval in the rolling direction is more than 20 mm.

10. A sheet of electrical steel with an oriented grain structure according to paragraph 6, in which: the absolute maximum value of the said interval in the rolling direction is more than 30 mm.

11. A grain-oriented electrical steel sheet according to any one of paragraphs 1-10, in which: A multitude of processing lines for controlling magnetic domains are grooves.

12. A grain-oriented electrical steel sheet according to any one of paragraphs 1-10, in which: A variety of processing lines for magnetic domain control are thermal deformations.

13. A method for producing a sheet of electrical steel with an oriented grain structure according to any one of paragraphs 1-10, wherein the method comprises: a magnetic domain imaging stage in which an image of the magnetic domain of the surface of a grain-oriented electrical steel sheet is obtained; a region determination step that determines a region having a magnetic domain wall spacing of more than 500 μm in a grain-oriented electrical steel sheet based on a magnetic domain image obtained in the magnetic domain imaging step; and a stage of forming processing lines for controlling magnetic domains, in which a processing line is formed for controlling magnetic domains on the surface of a grain-oriented electrical steel sheet after the stage of determining regions; wherein, at the stage of forming processing lines for controlling magnetic domains, the processing line for controlling magnetic domains is formed in a region in which the distance between the magnetic domain walls is more than 500 μm.

14. A method for producing a sheet of electrical steel with an oriented grain structure according to claim 13, in which: At the stage of forming processing lines for controlling magnetic domains, the processing line for controlling magnetic domains is formed by irradiation with a laser or electron beam.