Grain-oriented electrical steel sheet and method for manufacturing same
Disclosed are a grain-oriented electrical steel sheet and a method of manufacturing the same. The method for manufacturing a grain-orientated electrical steel sheet according to an exemplary embodiment of the present invention includes: providing an electrical steel sheet before forming primary recrystallization or after forming the primary recrystallization; and forming a groove in a surface of the electrical steel sheet by radiating laser and simultaneously spraying gas onto the electrical steel sheet, in which energy density E d and a laser scanning speed V s of the radiated laser satisfy the following conditions, 1.0 J/mm 2 ≤E d ≤5.0 J/mm 2 , 0.0518 mm/μsec≤ V s ≤0.2 mm/μsec.
1. A grain-oriented electrical steel sheet, which has a surface which is formed with grooves for a magnetic domain refinement treatment,
wherein a scattering alloy layer in the groove is eroded in a Goss texture during a recrystallization annealing process,
wherein when a thickness of the scattering alloy layer on a bottom surface of the groove is defined as T B , and a thickness of the scattering alloy layer at a point that is one-half the distance between any one end of the groove and the bottom surface of the groove is defined as T L , T B /T L is 0.2 to 0.8, and
wherein the groove is formed at an angle greater than 0° and equal to or smaller than 5° with respect to the width direction of the electrical steel sheet.
2. The grain-oriented electrical steel sheet of claim 1 , wherein:
a thickness of the scattering alloy layer is 4% to 12% of a depth of the groove.
3. The grain-oriented electrical steel sheet of claim 2 , wherein:
the depth of the groove is 4% to 11% of a thickness of the electrical steel sheet.
4. The grain-oriented electrical steel sheet of claim 3 , wherein:
the groove is formed diagonally with respect to a width direction of the electrical steel sheet.
5. The grain-oriented electrical steel sheet of claim 1 , wherein:
three to six grooves are intermittently formed in the width direction of the electrical steel sheet.
6. A method of manufacturing a grain-oriented electrical steel sheet, the method comprising:
providing an electrical steel sheet before forming primary recrystallization or after forming the primary recrystallization; and
forming a groove in a surface of the electrical steel sheet by radiating laser and simultaneously spraying gas onto the electrical steel sheet,
wherein energy density E d and a laser scanning speed V s of the radiated laser satisfy the following conditions,
1.0 J/mm 2 ≤E d ≤5.0 J/mm 2 ,
0.0518 mm/μsec≤ V s ≤0.2 mm/μsec,
wherein a scattering alloy layer in the groove is eroded in a Goss texture during a recrystallization annealing process, and
wherein when a thickness of the scattering alloy layer on a bottom surface of the groove is defined as T B , and a thickness of the scattering alloy layer at a point that is one-half the distance between any one end of the groove and the bottom surface of the groove is defined as T L , T B /T L is 0.2 to 0.8, and
wherein the groove is formed at an angel greater than 0° and equal to or smaller than 5° with respect to the width direction of the electrical steel sheet.
7. The method of claim 6 , wherein:
pressure of the sprayed gas is 0.2 kg/cm 2 to 5.0 kg/cm 2 .
8. The method of claim 7 , wherein:
an angle formed between the spray direction of the gas and the laser radiation direction is 0° to 50° (here, a state in which the angle formed between the spray direction of the gas and the laser radiation direction is 0° means that the spray direction of the gas and the laser radiation direction are parallel to each other).
9. The method of claim 8 , wherein:
in the radiating of the laser, a laser beam is radiated on the surface of the electrical steel sheet at an angle greater than 0° and equal to or smaller than 5° with respect to a width direction of the electrical steel sheet.
10. The method of claim 9 , wherein:
in the radiating of the laser, a movement speed V L of the electrical steel sheet is at least 0.9 m/s.
11. The method of claim 10 , wherein:
in the radiating of the laser,
when a beam length in the width direction of the electrical steel sheet is d t , and a beam length in a rolling direction of the electrical steel sheet is L, a light collecting shape of the laser satisfies the following condition,
0.20≤ L/d t ≤1.0.
12. The method of claim 11 , wherein:
d t is 50 μm or smaller.
13. The method of claim 12 , wherein:
in the radiating of the laser,
a scattering alloy layer in which a melted portion of the electrical steel sheet by the radiation of the laser scatters and is resolidified is generated.
14. The method of claim 13 , wherein:
a thickness of the scattering alloy layer is 4% to 12% of a depth of the groove.
15. The method of claim 14 , wherein:
in the radiating of the laser,
the laser is radiated diagonally with respect to a width direction of the electrical steel sheet.
16. The method of claim 15 , wherein:
in the radiating of the laser,
the laser is radiated at an angle greater than 0° and equal to or smaller than 5° with respect to the width direction of the electrical steel sheet.
17. The method of claim 16 , wherein:
in the radiating of the laser,
three to six grooves are intermittently formed in the width direction of the electrical steel sheet.