A grain-oriented electrical steel sheet according to the present embodiment is a grain-oriented electrical steel sheet having a groove formed on a surface, in which, in a cross section of the grain-oriented electrical steel sheet orthogonal to the groove, a KAM value is 0.1 or more and 3.0 or less in a region on a central side in a thickness direction of the grain-oriented electrical steel sheet with respect to the groove, the region being surrounded by a square having one side in contact with a groove bottom of the groove and having a length of 50 μm in each side.

Provided is a grain-oriented electrical steel sheet that combines low iron loss and low magnetostriction, together with an advantageous production method therefor. A grain-oriented electrical steel sheet comprises a linear strain portion extending in a direction intersecting a rolling direction of the grain-oriented electrical steel sheet, wherein the linear strain portion has a stress distribution in which a compressive stress region and a tensile stress region alternate in a longitudinal direction of the linear strain portion. The linear strain portion is formed by vibrating the grain-oriented electrical steel sheet in a sheet thickness direction, while irradiating a surface of the grain-oriented electrical steel sheet with an electron beam by repeatedly moving and detaining the electron beam in the direction intersecting the rolling direction of the grain-oriented electrical steel sheet.

Disclosed is a grain-oriented electrical steel sheet including: closure domains, each containing a discontinuous region at a part thereof and extending at an angle within 30° with respect to a transverse direction of the steel sheet, wherein a closure domain overlapping portion in the discontinuous region on one surface of the steel sheet has a length α in the transverse direction that is longer than a length β in the transverse direction of the closure domain overlapping portion on the other surface of the steel sheet, and the length α satisfies 0.5≤α≤5.0 and the length β satisfies 0.2α≤β≤0.8α. Consequently, the iron loss and the deterioration of magnetostrictive properties are suppressed in discontinuous regions, which would be inevitably formed when magnetic domain refining treatment is performed using a plurality of irradiation devices.

In a grain-oriented electrical steel sheet, comprising magnetic domains refined by a plurality of linear grooves in a surface of a steel sheet, each of the linear grooves is provided on its floor with a plurality of recessed parts aligned in a direction in which the linear groove extends, at a predetermined interval p (μm), and the recessed part is made to have a predetermined depth d (μm). In this way, it is possible to provide a grain-oriented electrical steel sheet having further improved iron loss properties while having reduced magnetic flux density reduction.

The grain-oriented electrical steel sheet according to the present embodiment is a grain-oriented electrical steel sheet having a base steel sheet (1), an intermediate layer (4) disposed to be in contact with the base steel sheet (1), and an insulation coating (3) disposed to be in contact with the intermediate layer (4). The grain-oriented electrical steel sheet according to the present embodiment includes a surface of the base steel sheet (1) having a strain region (D) which extends in a direction intersecting a rolling direction of the base steel sheet (1), and a crystalline phosphorus oxide M.sub.2P.sub.4O.sub.13 present in the insulation coating (3) on the strain region (D) in a cross-sectional view of a surface parallel to the rolling direction and a sheet thickness direction of the base steel sheet (1). (M means at least one or both of Fe and Cr.)

A method for producing a grain oriented electrical steel sheet includes a decarburization annealing process where an oxidation degree PH.sub.2O/PH.sub.2 is controlled and pickling is conducted after decreasing temperature, an annealing separator applying process where a mass ratio of MgO and Al.sub.2O.sub.3 in an annealing separator is controlled, a final annealing process where an oxidation degree is controlled when atmosphere includes hydrogen or a dew point is controlled when atmosphere consists of inert gas, an annealing separator removing process where water-washing is conducted using solution with inhibitor, and an insulation coating forming process where a mass ratio of phosphoric acid and metal compound in insulation coating forming solution is controlled.

A method for producing a grain oriented electrical steel sheet includes a decarburization annealing process where an oxidation degree PH.sub.2O/PH.sub.2 is controlled, an annealing separator applying process where a mass ratio of MgO and MCl in an annealing separator is controlled, a final annealing process where an oxidation degree is controlled when atmosphere includes hydrogen or a dew point is controlled when atmosphere consists of inert gas without hydrogen, and an insulation coating forming process where a baking temperature and a heat treatment temperature are controlled.

A grain-oriented electrical steel sheet according to the present invention includes a silicon steel sheet as a base steel sheet, and when an average value of amplitudes in a wavelength range of 20 to 100 μm among wavelength components obtained by performing Fourier analysis on a measured cross-sectional curve parallel to a sheet width direction of the silicon steel sheet is set as ave-AMP.sub.C100, ave-AMP.sub.C100 is 0.0001 to 0.050 μm.

An embodiment of the present invention provides a grain-oriented electrical steel sheet, including: a linear groove formed in a direction crossing a rolling direction on one surface or both surfaces of an electrical steel sheet; and a linear thermal shock portion formed in the direction crossing the rolling direction on one surface or both surfaces of the electrical steel sheet. The groove is formed in plural along the rolling direction, a distance D2 between the groove and the thermal shock portion is 0.2 to 0.5 times a distance D1 between the grooves, and a distance D3 between the thermal shock portions is 0.2 to 3.0 times the distance D1 between the grooves.

To optimize equipment and processes to enhance magnetic domain refinement efficiency and to enhance workability to improve processing capability, a method of refining a magnetic domain of a grain-oriented electrical steel plate includes zigzag controlling for transferring the steel plate without being inclined in right and left directions along a production line center, steel plate support roll position adjusting for controlling a position of the steel plate in up and down directions while supporting the steel plate, laser beam irradiating for irradiating a laser beam to a surface of the steel plate to melt the steel plate to form a groove in the surface of the steel plate, and removing for absorbing and removing radiant heat due to reflection of the laser beam irradiated to the surface of the steel plate during the laser beam irradiating.