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

Claims

1. A sheet of electrical steel with an oriented grain structure containing on the surface: a plurality of processing lines for controlling magnetic domains running in a direction intersecting the rolling direction; magnetic domain control area, which is an area within 10 mm from the processing line for controlling magnetic domains; non-magnetic domain control area, which is an area at a distance of more than 10 mm from all magnetic domain control processing lines, in this case the average value the absolute values ​​of the angles β in the region without control of magnetic domains and the average value |βDr| of the absolute values ​​of the angles β in the region of control of magnetic domains satisfy the following formula (5) |βDr|-|βNDr|≤-0.1° (5).

2. A grain-oriented electrical steel sheet according to claim 1, wherein the average value of the distances between magnetic domain walls in the region without magnetic domain control is 500 μm or less.

3. A grain-oriented electrical steel sheet according to claim 1 or 2, wherein the absolute maximum value of the distances between magnetic domain walls in the region without magnetic domain control is 1000 μm or less.

4. A grain-oriented electrical steel sheet according to any one of claims 1 to 3, wherein the plurality of processing lines for controlling magnetic domains are grooves.

5. A grain-oriented electrical steel sheet according to claim 4, wherein the absolute maximum value of the groove depth on the processing line for controlling magnetic domains is non-uniform at each measurement point of the groove depth.

6. A sheet of electrical steel with an oriented grain structure according to paragraph 5, in which 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 at intervals of 5 mm in the direction perpendicular to the rolling direction in the evaluation area, when each of the plurality of intersection points of the imaginary lines and the plurality of processing lines for controlling magnetic domains is set as a magnetic domain refinement point, the absolute maximum value of the groove depth in units of μm measured at each of the magnetic domain refinement points is set as D m , and the dispersion D m is given by σ(D m ) 2 , is satisfied σ(D m ) 2 >3.

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7. A grain-oriented electrical steel sheet according to claim 5 or 6, in which in the case where a square evaluation area having a side length of 50 mm and a side parallel to the rolling direction is set on the surface, and in addition, imaginary lines parallel to the rolling direction and having a length of 50 mm are set at intervals of 5 mm in a direction perpendicular to the rolling direction in the evaluation area, each of a plurality of intersection points of the imaginary lines and a plurality of processing lines for controlling magnetic domains is set as a magnetic domain refinement point, the arithmetic mean value of the absolute maximum values ​​of the groove depths in units of μm measured at each of the magnetic domain refinement points having an angle β of less than 2°, of the magnetic domain refinement points, is set as D m(β<2), and the arithmetic mean value of the absolute maximum values ​​of the groove depth in units of μm at each of the magnetic domain grinding points having an angle β of 2° or more, from the magnetic domain grinding points, is set as D m(β≥2) , is satisfied D m(β<2) > D m(β≥2) .

8. A grain-oriented electrical steel sheet according to any one of claims 1 to 3, wherein the plurality of processing lines for controlling magnetic domains are thermal deformations in which a tensile stress of 40 MPa or more is introduced.

9. A grain-oriented electrical steel sheet according to claim 8, wherein the absolute maximum value of the tensile stress introduced in the thermal deformation on the processing line for controlling magnetic domains is non-uniform at each point of measurement of the tensile stress.

10. A grain-oriented electrical steel sheet according to claim 9, in which 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 at intervals of 5 mm in the direction perpendicular to the rolling direction in the evaluation area, when each of the plurality of intersection points of the imaginary lines and the plurality of processing lines for controlling the magnetic domains is set as a magnetic domain refinement point, the absolute maximum value of the tensile stress in units of MPa introduced in the thermal deformation measured at each of the magnetic domain refinement points is set as TS m , and the dispersion of TS m is given as σ(TS m ) 2 , is satisfied: σ(TS m ) 2 >5.

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11. The grain-oriented electrical steel sheet according to claim 9 or 10, wherein, in the case where a square evaluation region having a side length of 50 mm and a side parallel to the rolling direction is defined on the surface, and in addition, imaginary lines parallel to the rolling direction and having a length of 50 mm are defined at intervals of 5 mm in a direction perpendicular to the rolling direction in the evaluation region, each of a plurality of intersection points of the imaginary lines and a plurality of processing lines for controlling magnetic domains is defined as a magnetic domain refinement point when TS m(β<2) is the arithmetic mean of the absolute maximum values ​​of tensile stress in units of MPa introduced into thermal deformation, measured at each of the magnetic domain refinement points having an angle β of less than 2°, from the magnetic domain refinement points, and TS m(β≥2)is the arithmetic mean of the absolute maximum values ​​of tensile stress in units of MPa introduced into thermal deformation, measured at each of the magnetic domain refinement points having an angle β of 2° or more, from the magnetic domain refinement points, satisfied: TS m(β<2) >TS m(β≥2) .

12. A method for producing a sheet of electrical steel with an oriented grain structure, wherein the method comprises a magnetic domain imaging stage, in which an image of the magnetic domain of the surface of a sheet of electrical steel with an oriented grain structure is obtained; a region setting stage in which a region is set having a distance between magnetic domain walls of more than 500 μm in a sheet of electrical steel with an oriented grain structure based on the magnetic domain image obtained in the magnetic domain image obtaining stage; a stage of forming processing lines for controlling magnetic domains, at which a processing line is formed for controlling magnetic domains on the surface of a sheet of electrical steel with an oriented grain structure; wherein, at the stage of forming processing lines for controlling magnetic domains, a processing line for controlling magnetic domains is formed in a region having a distance between magnetic domain walls of more than 500 μm, so that the region includes a magnetic domain control region, which is a region within 10 mm from the processing line for controlling magnetic domains, and a region without magnetic domain control, which is a region at a distance of more than 10 mm from all processing lines for controlling magnetic domains, and in which the average value the absolute values ​​of the angles β in the region without control of magnetic domains and the average value |βDr| of the absolute values ​​of the angles β in the region of control of magnetic domains satisfy |βDr|-|βND|≤-0.1°.

13. A method for manufacturing a sheet of electrical steel with an oriented grain structure according to claim 12, wherein 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.