US 12,278,024 B2
Method of making an electrical steel sheet provided with insulating coating
Kazumichi Sashi, Chiba (JP); Nobuko Nakagawa, Chiba (JP); Naoki Muramatsu, Chiba (JP); Chiyoko Tada, Chiba (JP); and Nobue Fujibayashi, Chiba (JP)
Assigned to JFE Steel Corporation, Tokyo (JP)
Filed by JFE Steel Corporation, Tokyo (JP)
Filed on Oct. 5, 2021, as Appl. No. 17/493,900.
Application 17/493,900 is a division of application No. 16/517,760, filed on Jul. 22, 2019, granted, now 11,177,052.
Application 16/517,760 is a division of application No. 15/039,161, granted, now 10,403,417, issued on Sep. 3, 2019, previously published as PCT/JP2014/005661, filed on Nov. 11, 2014.
Claims priority of application No. 2013-246473 (JP), filed on Nov. 28, 2013; and application No. 2014-133514 (JP), filed on Jun. 30, 2014.
Prior Publication US 2022/0028576 A1, Jan. 27, 2022
Int. Cl. C21D 8/12 (2006.01); C22C 38/00 (2006.01); C22C 38/06 (2006.01); H01B 3/10 (2006.01); H01B 7/02 (2006.01); H01F 1/18 (2006.01)
CPC H01B 7/02 (2013.01) [C21D 8/1283 (2013.01); C22C 38/00 (2013.01); C22C 38/06 (2013.01); H01B 3/10 (2013.01); H01F 1/18 (2013.01)] 17 Claims
OG exemplary drawing
 
1. An insulated electrical steel sheet consisting of:
an electrical steel sheet; and
an insulating coating formed on the electrical steel sheet by a method comprising:
preparing a treatment solution that does not contain an Fe compound by adding an Si compound to water;
applying the treatment solution to a surface of the electrical steel sheet;
leaving the treatment solution on the surface of the electrical steel sheet to allow Fe in the electrical steel sheet to be dissolved in the treatment solution; and
baking the treatment solution to form the insulating coating such that a coating weight of Si in the insulating coating in terms of SiO2 is 50% to 99% of the total coating weight, and a ratio (Fe/Si) of content of Fe to content of Si in the insulating coating is 0.01 to 0.6 on a molar basis.