Abstract: The present invention provides grain-oriented electrical sheet more superior in watt loss compared with the past by dividing the watt loss of grain-oriented electrical sheet introducing strain by firing of a laser beam etc. into hysteresis loss and eddy current loss and, in particular from the viewpoint of the eddy current loss, quantitatively suitably controlling the distribution of the strain and residual stress in the sheet thickness direction, that is, grain-oriented electrical sheet obtained by firing a laser beam etc.

Abstract: An object of the present invention is to provide a grain-oriented electrical steel sheet with low core loss and low magnetostriction and a method for producing the same. The grain-oriented electrical steel sheet is excellent in reduced core loss and magnetostriction while under a high flux density of 1.9 T, comprises a refined magnetic domain comprising a laser irradiated portion which has melted and resolidified to form a solidified layer, wherein the thickness of the solidified layer is 4 ?m or less. The grain-oriented electrical steel sheet may further comprise a laser irradiated portion where a surface roughness Rz is small and a cross section viewed from a transverse direction has a concave portion having a width of 200 ?m or less and a depth of 10 ?m or less for further improvement.

Abstract: The present invention provides a method of production of grain-oriented electrical steel sheet greatly reducing the Watt loss of the grain-oriented electrical steel sheet and making the magnetostriction as small as possible, that is, a method of production of grain-oriented electrical steel sheet with small magnetostriction by improving the magnetic properties by irradiation by a finely focused laser beam comprising using a power modulated laser controlled in maximum power density to 1×102 to 1×104 W/mm2 to optimize the amount of strain given by laser irradiation in both the sheet width direction and rolling direction and, in particular, to make the modulation duty 70% to less than 100%.

Abstract: Technology scanning and irradiating grain-oriented electrical steel sheet moving in a rolling direction at a speed Vl with an elliptical spot formed by a laser beam in the width direction at Vc to improve the core loss of the grain-oriented electrical steel sheet, which adjusts the angle ?s formed by the scan direction of the elliptical beam and the long axis of the ellipse based on the equation ?s=tan?1(Vl/Vc) and which constructs the system for adjusting the ?s by an optical system for laser irradiation comprised of a cylindrical lens telescope, scan mirror, and f? lens arranged in that order, a system for changing the angle of the cylindrical lens telescope with respect to the scan direction of the scan mirror, and a system for changing the distance between lenses.

Abstract: The present invention provides a grain-oriented electrical steel sheet with an extremely low core loss by scanning by a small focused laser beam spot and a method of production of the same, that is, a grain-oriented electrical steel sheet improved in electrical characteristics by scanning by a continuous wave fiber laser of the TEM00 mode with a wavelength ? of 1.07???2.10 ?m substantially perpendicular to the steel sheet rolling direction and at substantially constant spacing and a method of production of the same, wherein a rolling direction focused spot diameter d (mm) of the irradiated beam, a linear scan rate V (mm/s) of the laser beam, an average output P (W) of the laser, a width of the formed laser scribing traces or with of the electrical domains Wl (mm), and a rolling direction Pl (mm) of the laser scribing traces are in the following ranges: 0<d?0.20 0.001?P/V?0.012 0<Wl?0.20 1.5?Pl?11.0.

Abstract: A semiconductor laser device including a laser element stack array emitting a two-dimensional array shaped group of laser beams consisting of rows of laser beams arranged linearly in parallel in a broken line configuration and optical elements arranged in front of the array, receiving rows of laser beams bent and collimated in a direction substantially perpendicular to the orientation of the broken line configuration. Laser beams are emitted from emitters or groups of emitters and are rotated by right angles so as to convert the laser beams to a plurality of rows aligned in parallel in an approximate ladder rung configuration and the distance between center axes of the rows of laser beams is shortened to condense the laser beams by converting them to a group of laser beams emitted from a common object and thereby making all laser beams converge to a single image.

Abstract: The present invention provides a grain-oriented electrical steel sheet with an extremely low core loss by scanning by a small focused laser beam spot and a method of production of the same, that is, a grain-oriented electrical steel sheet improved in electrical characteristics by scanning by a continuous wave fiber laser of the TEM00 mode with a wavelength ? of 1.07???2.10 ?m substantially perpendicular to the steel sheet rolling direction and at substantially constant spacing and a method of production of the same, wherein a rolling direction focused spot diameter d (mm) of the irradiated beam, a linear scan rate V (mm/s) of the laser beam, an average output P (W) of the laser, a width of the formed laser scribing traces or with of the electrical domains Wl (mm), and a rolling direction Pl (mm) of the laser scribing traces are in the following ranges: 0<d?0.20 0.001?P/V?0.012 0<Wl?0.20 1.5?Pl?11.

Abstract: A low core loss grain-oriented electrical steel sheet that does not have a significant deterioration in a magnetic flux density and a decrease of a space factor, and which may withstand stress-relieving annealing is provided. Melted and re-solidified layers can be formed on either or both of the surfaces of the grain-oriented electrical steel sheet that extend in a direction that is perpendicular to the rolling direction (e.g., in the direction of the width thereof), at a cyclic interval of not less than approximately 2 mm to less than approximately 5 mm in the rolling direction. The melted and re-solidified layers may be provided on each surface of the grain-oriented electrical steel sheet, and can have an aspect ratio that is a ratio of the depth to the width of the melted and re-solidified layer of not less than approximately 0.20 and a depth of not less than approximately 15 ?m. In addition, the melted and re-solidified layers can be formed by using a laser.

Abstract: A semiconductor laser device including a laser element stack array emitting a two-dimensional array shaped group of laser beams consisting of rows of laser beams arranged linearly in parallel in a broken line configuration and optical elements arranged in front of the array, receiving rows of laser beams bent and collimated in a direction substantially perpendicular to the orientation of the broken line configuration. Laser beams are emitted from emitters or groups of emitters and are rotated by right angles so as to convert the laser beams to a plurality of rows aligned in parallel in an approximate ladder rung configuration and the distance between center axes of the rows of laser beams is shortened to condense the laser beams by converting them to a group of laser beams emitted from a common object and thereby making all laser beams converge to a single image.

Abstract: A low core loss grain-oriented electrical steel sheet that does not have a significant deterioration in a magnetic flux density and a decrease of a space factor, and which may withstand stress-relieving annealing is provided. Melted and re-solidified layers can be formed on either or both of the surfaces of the grain-oriented electrical steel sheet that extend in a direction that is perpendicular to the rolling direction (e.g., in the direction of the width thereof), at a cyclic interval of not less than approximately 2 mm to less than approximately 5 mm in the rolling direction. The melted and re-solidified layers may be provided on each surface of the grain-oriented electrical steel sheet, and can have an aspect ratio that is a ratio of the depth to the width of the melted and re-solidified layer of not less than approximately 0.20 and a depth of not less than approximately 15 &mgr;m. In addition, the melted and re-solidified layers can be formed by using a laser.