US 12,334,237 B2
Non-oriented electrical steel sheet and method for producing same
Hiroyasu Fujii, Tokyo (JP); Jun Maki, Tokyo (JP); Kazutoshi Takeda, Tokyo (JP); Akira Akagi, Tokyo (JP); and Hiroyuki Mimura, Tokyo (JP)
Assigned to NIPPON STEEL CORPORATION, Tokyo (JP)
Appl. No. 17/778,178
Filed by NIPPON STEEL CORPORATION, Tokyo (JP)
PCT Filed Nov. 20, 2020, PCT No. PCT/JP2020/043479
§ 371(c)(1), (2) Date May 19, 2022,
PCT Pub. No. WO2021/100867, PCT Pub. Date May 27, 2021.
Claims priority of application No. 2019-210860 (JP), filed on Nov. 21, 2019.
Prior Publication US 2023/0033301 A1, Feb. 2, 2023
Int. Cl. H01F 1/147 (2006.01); B05D 3/02 (2006.01); B05D 7/14 (2006.01); C08K 3/32 (2006.01); H01F 41/02 (2006.01)
CPC H01F 1/147 (2013.01) [B05D 3/0254 (2013.01); B05D 7/14 (2013.01); C08K 3/32 (2013.01); H01F 41/02 (2013.01); C08K 2003/327 (2013.01); C08K 2003/328 (2013.01)] 9 Claims
 
1. A non-oriented electrical steel sheet, comprising:
a base metal steel sheet, and
a composite coating film composed of a Zn-containing phosphate and an organic resin, the composite coating film being formed on a surface of the base metal steel sheet,
wherein:
a content of Zn in the composite coating film is 10 mg/m2 or more per side, and
a product of an amount of oxygen in the base metal steel sheet and a sheet thickness of the base metal steel sheet is 50 ppm·mm or less, and
wherein a red rust area ratio of a stacked cut edge of the non-oriented electrical steel sheet at a time point at which a spraying time reached 8 hours is less than 20% when the non-oriented electrical steel sheet with the composite coating film is cut with a shearing machine into 20 mm×50 mm size, twenty cut non-oriented electrical steel sheets are stacked such that a total height of their cut edges is 10 mm, and evaluation of corrosion resistance is performed by a salt spray test in accordance with JIS Z 2371 with respect to one 10 mm×50 mm stacked cut edge of the stacked body wherein a NaCl concentration of a salt aqueous solution for the test is 5% by mass and a temperature in the vicinity of a test specimen retainer in a spray chamber is set to 35° C.