Grain oriented electrical steel sheet with low iron loss and production method for same

A grain oriented electrical steel sheet with low iron loss, comprising:

• a metal part containing Si:
• about 2.5 to about 5.0 mass % and Cr:
• about 0.2 to about 0.7 mass %,
• an insulation coating formed on a surface of the metal part and made of one or more layers, and
• a plurality of grooves formed in the surface of the metal part which linearly extend at an angle of not larger than about 45° relative to the direction perpendicular to the rolling direction,
• wherein magnetic flux density B8 satisfies formula (3) and an array interval D (mm) of said grooves satisfies formula (4):
• B8≧(2.21−0.0604(Si)−0.0294(Cr))×0.960−0.0030d (3)
• 1+5(Cr)≦D≦[8]5+5(Cr) (4), and
• wherein (Si) and (Cr) represent mass percentages of Si and Cr in the metal part and wherein B8 is measured in T, d is a depth of the grooves measured in μm, and D is measured in mm.

A grain oriented electrical steel sheet with low iron loss, comprising:

• a metal part containing Si:
• about 2.5 to about 5.0 mass %. Cr:
• about 0.05 to about 1.0 mass %, and Bi:
• about 0.0005 to about 0.08 mass %,
• an insulation coating formed on a surface of the metal part and made of one or more layers, and
• a plurality of grooves formed in the surface of the metal part which linearly extend at an angle of not larger than about 45° relative to the direction perpendicular to the rolling direction,
• wherein magnetic flux density B8 satisfies formula (3) and an array interval D (mm) of said grooves satisfies formula (4):
• B8≧(2.21−0.0604(Si)−0.0294(Cr))×0.960−0.0030d (3)
• 1+5(Cr)≦D≦[8]5+5(Cr) (4), and
• wherein (Si) and (Cr) represent mass percentages of Si and Cr in the metal part and wherein B8 is measured in T, d is a depth of the grooves measured in μm, and D is measured in mm.