	US 12,331,377 B2
	Grain-oriented electrical steel sheet, intermediate steel sheet for grain-oriented electrical steel sheet, and methods for manufacturing same
Shinji Yamamoto, Tokyo (JP); Yoshiyuki Ushigami, Tokyo (JP); and Shinsuke Takatani, Tokyo (JP)
Assigned to NIPPON STEEL CORPORATION, Tokyo (JP)
Appl. No. 17/421,758
Filed by NIPPON STEEL CORPORATION, Tokyo (JP)
PCT Filed Jan. 16, 2020, PCT No. PCT/JP2020/001170 § 371(c)(1), (2) Date Jul. 9, 2021, PCT Pub. No. WO2020/149334, PCT Pub. Date Jul. 23, 2020.
Claims priority of application No. 2019-005200 (JP), filed on Jan. 16, 2019.
Prior Publication US 2022/0090225 A1, Mar. 24, 2022
Int. Cl. H01F 1/18 (2006.01); C21D 3/04 (2006.01); C21D 6/00 (2006.01); C21D 8/00 (2006.01); C21D 8/12 (2006.01); C21D 9/46 (2006.01); C22C 38/00 (2006.01); C22C 38/02 (2006.01); C22C 38/04 (2006.01); C22C 38/06 (2006.01); H01F 41/02 (2006.01)

CPC C21D 9/46 (2013.01) [C21D 3/04 (2013.01); C21D 6/005 (2013.01); C21D 6/008 (2013.01); C21D 8/005 (2013.01); C21D 8/1222 (2013.01); C21D 8/1233 (2013.01); C21D 8/1255 (2013.01); C21D 8/1283 (2013.01); C22C 38/001 (2013.01); C22C 38/02 (2013.01); C22C 38/04 (2013.01); C22C 38/06 (2013.01); H01F 1/18 (2013.01); H01F 41/0233 (2013.01)]

3 Claims

1. A grain-oriented electrical steel sheet comprising:

a base steel sheet;

an intermediate layer that is formed on a surface of the base steel sheet and mainly contains silicon oxide; and

an insulation coating that is formed on a surface of the intermediate layer,

wherein a number density of oxide particles in a region from the surface of the base steel sheet to a depth of 10 μm toward an inside of the base steel sheet is 0.020 oxide particles/μm²or less,

an area rate of an intermediate layer-remaining region in which the intermediate layer does not peel off but remains in a region in which the insulation coating peels off after a bend test performed using a mandrel with a diameter of 10 to 16 mm according to JIS K 5600 May 1 (1999) is 20% or more, and

in a case where the evaluation area of insulation peeling defined by the following expression is less than 5%, the area rate of the intermediate layer-remaining region is re-evaluated by using a mandrel having a smaller diameter and is 20% or more,

(Evaluation area of insulation coating peeling)=(diameter of mandrel)×(ratio of circumference to diameter)÷2.