US 2026/0193749 A1Published application

Grain-oriented electrical steel sheet and manufacturing method therefor

AssigneeNippon Steel Corporation

InventorsMasaru TAKAHASHI, Masato YASUDA, Nobusato MORISHIGE, Naoki WADA, Masataka IWAKI, Hisashi MOGI

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Abstract

A grain-oriented electrical steel sheet includes: a silicon steel sheet; an oxide layer formed of one or more kinds of Mg, Al, and Si that is formed on a surface of the silicon steel sheet; and an insulating coating layer that is formed on a surface of the oxide layer, in which an oxide of one or more kinds of Mg, Al, and Si having an equivalent circle diameter of 0.1 to 3.0 μm is present at a density of 0.010 to 0.200 grains/μm2 in the silicon steel sheet in a range of 5 μm in a sheet thickness direction from an interface between the silicon steel sheet and the oxide layer, flat grains are present on the surface side of the silicon steel sheet, in a cross section in the sheet thickness direction, a length of grain boundaries of the flat grains accounts for 50% or more of a length of the interface between the silicon steel sheet and the oxide layer, and a plurality of linear thermal strains extending in a direction having an angle of 80 to 100° with respect to a rolling direction are formed on the surface of the silicon steel sheet at intervals of 1.0 to 20.0 mm in the rolling direction.

Claims5

Dependent claims

A grain-oriented electrical steel sheet comprising:

a silicon steel sheet;
an oxide layer formed of one or more kinds of Mg, Al, and Si that is formed on a surface of the silicon steel sheet;
and
an insulating coating layer that is formed on a surface of the oxide layer,
wherein an oxide of one or more kinds of Mg, Al, and Si having an equivalent circle diameter of 0.1 to 3.0 μm is present at a density of 0.010 to 0.200 grains/μm2 in a range of 5 μm in a sheet thickness direction from an interface between the silicon steel sheet and the oxide layer in the silicon steel sheet,
on the surface side of the silicon steel sheet, flat grains where an average thickness in a direction perpendicular to the surface is 0.5 to 5.0 μm, an aspect ratio that is a ratio of a grain width in a direction parallel to the surface to the average thickness is 1.5 or more, and a deviation of a crystal orientation from Goss orientation is 10° or more are present,
in a cross section in the sheet thickness direction, a length of grain boundaries of the flat grains accounts for 50% or more of a length of the interface between the silicon steel sheet and the oxide layer, and
a plurality of linear thermal strains extending in a direction having an angle of 80 to 100° with respect to a rolling direction are formed on the surface of the silicon steel sheet at intervals of 1.0 to 20.0 mm in the rolling direction.

5 more elements

A manufacturing method for a grain-oriented electrical steel sheet, the manufacturing method comprising:

a hot rolling step of heating and hot rolling a slab to obtain a hot rolled sheet;
a hot rolled sheet annealing step of annealing the hot rolled sheet after the hot rolling step;
a pickling step of pickling the hot rolled sheet after the hot rolled sheet annealing step;
a cold rolling step of cold rolling the hot rolled sheet after the pickling step to obtain a cold rolled sheet;
a grinding step of grinding a surface of the cold rolled sheet after the cold rolling step;
a contact step of bringing the cold rolled sheet after the grinding step into contact with an aqueous solution of pH 4.0 to 10.0;
a decarburization annealing step of performing decarburization annealing on the cold rolled sheet after the contact step;
a finish annealing step of applying an annealing separator to the cold rolled sheet after the decarburization annealing step and subsequently performing finish annealing to form an oxide layer formed of one or more kinds of Mg, Al, and Si on a surface of the cold rolled sheet that is a base steel sheet;
an insulating coating forming step of forming an insulating coating layer on a surface of the oxide layer after the finish annealing step to obtain a grain-oriented electrical steel sheet including the silicon steel sheet, the oxide layer, and the insulating coating layer;
and
a magnetic domain control step of irradiating a surface of the grain-oriented electrical steel sheet after the insulating coating forming step with a laser, an electron beam, or a plasma to form a plurality of linear thermal strains extending in a direction having an angle of 80 to 100° with respect to a rolling direction on the surface of the silicon steel sheet such that each of intervals in the rolling direction is 1.0 to 20.0 mm,
wherein in the grinding step, using abrasive grains having a Knoop hardness of 1000 or more or using abrasive paper, a roll, or a brush to which the abrasive grains are fixed, the surface of the cold rolled sheet is ground such that an amount of abrasion on at least one surface of the cold rolled sheet is 0.10 to 3.00 g/m2.

9 more elements

Dependencies are inferred from the claim text.