US 12,116,645 B2
Grain-oriented electrical steel sheet and magnetic domain refinement method thereof
Se-Min Park, Pohang-si (KR); Seong-Cheol Hong, Pohang-si (KR); Hyun-Chul Park, Pohang-si (KR); Jung-Moon Kang, Pohang-si (KR); Chang-Ho Kim, Pohang-si (KR); Won-Gul Lee, Pohang-si (KR); and Ki-Young Min, Pohang-si (KR)
Assigned to POSCO CO., LTD, Pohang-si (KR)
Appl. No. 17/277,879
Filed by POSCO, Pohang-si (KR)
PCT Filed May 23, 2019, PCT No. PCT/KR2019/006220
§ 371(c)(1), (2) Date Mar. 19, 2021,
PCT Pub. No. WO2020/059999, PCT Pub. Date Mar. 26, 2020.
Claims priority of application No. 10-2018-0114110 (KR), filed on Sep. 21, 2018.
Prior Publication US 2022/0119901 A1, Apr. 21, 2022
Int. Cl. C21D 8/02 (2006.01)
CPC C21D 8/0226 (2013.01) [C21D 8/0205 (2013.01); C21D 8/0236 (2013.01); C21D 2201/05 (2013.01)] 6 Claims
OG exemplary drawing
 
1. A magnetic domain refining method of a grain-oriented electrical steel sheet, comprising:
preparing a grain-oriented electrical steel sheet; and
forming a groove on one surface of the grain-orientation electrical steel sheet by irradiating a laser in a direction intersecting with a rolling direction,
wherein the forming of the groove includes forming a gradient section and forming a uniform section,
in the forming of the gradient section, a laser in which an average energy density is in the range of 0.05 to 0.5 J/mm2 is irradiated, and in the forming of the uniform section, a laser in which the average energy density is more than 0.5 J/mm2 to 5 J/mm2 is irradiated, and
lengths of the gradient section and the uniform section satisfy Equation 1 below:
0.1≤[GSL]/[USL]≤0.5  [equation 1]
wherein equation 1, [GSL] represents the length of the gradient section in μm and [USL] represents the length of the uniform section in mm.