We Claim: 【Claim 1】
A method of refining a magnetic domain of a grain-oriented electrical
steel plate, the method comprising:
5 steel plate support roll position adjusting for controlling a position of the
steel plate in up and down directions while supporting the steel plate transferred in a production line;
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
10 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.
【Claim 2】
15 The method of claim 1, wherein:
the laser beam irradiating further includes angle changing for changing an angle of an irradiation line of the laser beam irradiated to the surface of the steel plate.
20 【Claim 3】
The method of claim 2, wherein:
the angle changing includes changing the angle of the irradiation line of the laser beam in a width direction of the steel plate to a range of ±4°.

【Claim 4】
The method of claim 1, wherein:
the laser beam irradiating includes irradiating the laser beam at a position spaced apart from a center of a steel plate support roll from a reference point, which is determined as a laser beam irradiation position when an irradiation direction of a laser beam passes through a center axis of the steel plate support roll with respect to the surface of the steel plate transferred to contact the surface of the steel plate support roll in a circular arc form, along an external circumferential surface at a predetermined angle.
【Claim 5】
The method of claim 4, wherein:
the laser beam irradiating includes irradiating a laser beam in a spacing range of 3 to 7° along an external circumferential surface at a center of the steel plate support roll with respect to the reference point.
【Claim 6】
The method of any one of claim 1 to claim 5, wherein:
the removing includes:
heat-exchanging and absorbing radiant heat of a laser beam through a cooling block installed below an optical system for irradiating a laser beam corresponding to a reflected position of a laser beam reflected by the steel plate;

and
circulating a coolant in the cooling block to maintain cooling temperature of the cooling block.
【Claim 7】
The method of claim 6, wherein: the removing further includes:
detecting a flow rate of the coolant supplied to the cooling block; and controlling driving of a laser oscillator when the fed flow rate of the coolant is abnormal.
【Claim 8】
The method of claim 6, further comprising
setting and maintaining for setting and maintaining an internal operation environment of a laser room in which laser beam irradiation is performed, wherein
the setting and maintaining includes:
isolating an internal portion of the laser room from the outside to prevent external pollutant from being introduced; and
controlling temperature, pressure, and humidity inside the laser room.
【Claim 9】
The method of claim 6, further comprising

tension controlling for applying tension to the steel plate to maintain the steel plate in a flat state.
【Claim 10】
The method of claim 6, further comprising
zigzag controlling for transferring the steel plate without being inclined in right and left directions along a production line center.
【Claim 11】
The method of claim 6, further comprising
post processing for removing hill up and spatter formed on the surface of the steel plate via the laser beam irradiation.
【Claim 12】
A device for refining a magnetic domain of a grain-oriented electrical steel plate, comprising:
steel plate support roll position adjusting equipment configured to control a position of the steel plate in up and down directions while supporting the steel plate transferred in a production line;
laser beam irradiation equipment configured to irradiate 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
an absorption portion configured to absorb and remove radiant heat due

to reflection of the laser beam irradiated to the surface of the steel plate from the laser beam irradiation equipment.
【Claim 13】
The device of claim 12, further comprising
a laser room configured to isolate the steel plate support roll position adjusting equipment and the laser beam irradiation equipment from the outside to provide an operation environment for laser beam irradiation.
【Claim 14】
The device of claim 13, wherein:
the laser room includes:
an over pressure device configured to accommodate the laser beam irradiation equipment and the steel plate support roll position control equipment to form an internal space to be isolated from the outside, including an inlet and an output at opposite sides in a transferred direction of the steel plate, and formed therein to increase internal pressure of the laser room compared with external pressure;
an optical system lower frame configured to separate an upper space in which an optical system of the laser beam irradiation equipment is positioned from a lower space through which the steel plate is passed; and
an isothermal-isohumidity controller configured to control temperature and humidity inside the laser room.

【Claim 15】
The device of claim 12, wherein
the laser beam irradiation equipment irradiates the laser beam at a position spaced apart from a center of a steel plate support roll from a reference point, which is determined as a laser beam irradiation position when an irradiation direction of a laser beam passes through a center axis of the steel plate support roll with respect to the surface of the steel plate transferred to contact the surface of the steel plate support roll in a circular arc form, along an external circumferential surface at a predetermined angle.
【Claim 16】
The device of claim 15, wherein
the laser beam irradiation equipment irradiates a laser beam in a spacing range of 3 to 7° along an external circumferential surface at a center of the steel plate support roll with respect to the reference point.
【Claim 17】
The device of claim 12, wherein
the optical system is configured to be rotatable by a driver and to be rotated with respect to the steel plate to change an irradiation angle of the laser beam in a width direction of the steel plate.
【Claim 18】

The device of claim 12, further comprising
tension control equipment configured to apply tension to the steel plate to maintain the steel plate in a flat state.
【Claim 19】
The device of claim 12, further comprising
zigzag control equipment configured to transfer the steel plate without eing inclined in right and left directions along a production line center.
【Claim 20】
The device of claim 12, further comprising
post-processing equipment configured to remove hill up and spatter ormed on the surface of the steel plate.
【Claim 21】
The device of any one of claim 12 to claim 20, wherein: the absorption portion includes a cooling block installed below an optical ystem of the laser beam irradiation equipment corresponding to a reflected osition of the laser beam reflected by the steel plate and configured to absorb adiant heat of a reflected laser beam via heat exchange.
【Claim 22】
The device of claim 21, wherein:

the absorption portion further includes a cooling path formed in the cooling block and a supply portion configured to circulate and supply the coolant to the cooling block through a supply pipe connected to the cooling path.
【Claim 23】
The device of claim 22, wherein
the supply portion includes a heat exchanger installed on a coolant circulation line, a supply pump configured to supply the coolant passed through the heat exchanger, a flow switch configured to detect a fed flow rate of the coolant introduced into the cooling block along a circulation line according to driving of the supply pump, and a control circuit configured to control driving of the laser oscillator of the optical system based on a detected value of the flow switch.
【Claim 24】
The device of claim 22, wherein:
the cooling block forms a chemical vapor coating layer to prevent scattered melted iron from being attached to the surface.
【Claim 25】
The device of claim 22, wherein:
the cooling path of the cooling block includes a plurality of paths formed in a straight line through an external surface of the cooling block, and a plug

configured to block a path in the path to connect the paths in one direction at an intersection between the paths and formed in a zigzag form.
【Claim 26】
The device of claim 25, wherein:
the plug is fixedly installed to the cooling block via cogging of the cooling