Abstract: A grain-orientation electrical steel sheet according to an exemplary embodiment of the present invention includes a linear groove formed in a direction intersecting with the rolling direction, the groove includes the gradient section and the uniform section on a cross section including the transverse direction of the groove and the rolling surface normal direction of the steel sheet, and a length of the gradient section (GS) and the length of the uniform section (US) satisfy Equation 1 below. 0.1?[GSL]/[USL]?0.5??[Equation 1] In Equation 1, [GSL] represents the length (mm) of the gradient section and [USL] represents the length (mm) of the uniform section.

Abstract: A foreign substance collecting apparatus according to one embodiment of the present disclosure may comprise: a collection body unit formed with a suction port through which air including foreign substances flows in and a discharge port through which air removed of the foreign substances is discharged; and a mixing unit provided inside the collection body unit and disposed on a flow passage of the air, and forming a vortex in washing water contained therein by inducing a rotary flow of the air.