US 12,467,154 B2
Fe-based electroplated steel sheet, electrodeposition-coated steel sheet, automotive part, method of producing electrodeposition-coated steel sheet, and method of producing Fe-based electroplated steel sheet
Shunsuke Yamamoto, Tokyo (JP); Katsutoshi Takashima, Tokyo (JP); Yusuke Okumura, Tokyo (JP); Tomomi Kanazawa, Tokyo (JP); Katsuya Hoshino, Tokyo (JP); Takashi Kawano, Tokyo (JP); Takako Yamashita, Tokyo (JP); Hiroshi Matsuda, Tokyo (JP); and Yoichi Makimizu, Tokyo (JP)
Assigned to JFE STEEL CORPORATION, Tokyo (JP)
Appl. No. 18/250,978
Filed by JFE STEEL CORPORATION, Tokyo (JP)
PCT Filed Nov. 5, 2021, PCT No. PCT/JP2021/040871
§ 371(c)(1), (2) Date Apr. 28, 2023,
PCT Pub. No. WO2022/097734, PCT Pub. Date May 12, 2022.
Claims priority of application No. 2020-186206 (JP), filed on Nov. 6, 2020.
Prior Publication US 2024/0117517 A1, Apr. 11, 2024
This patent is subject to a terminal disclaimer.
Int. Cl. C25D 3/20 (2006.01); C21D 8/02 (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); C25D 5/36 (2006.01); C25D 5/50 (2006.01); C25D 7/06 (2006.01); C25D 3/26 (2006.01)
CPC C25D 3/20 (2013.01) [C21D 8/0236 (2013.01); C21D 8/0257 (2013.01); C21D 9/46 (2013.01); C22C 38/001 (2013.01); C22C 38/002 (2013.01); C22C 38/02 (2013.01); C22C 38/04 (2013.01); C22C 38/06 (2013.01); C25D 5/50 (2013.01); C25D 7/0614 (2013.01); C25D 3/26 (2013.01); C25D 5/36 (2013.01)] 3 Claims
OG exemplary drawing
 
1. A method of producing an Fe-based electroplated steel sheet, the method comprising:
subjecting a cold-rolled steel sheet containing Si in an amount of 0.1 mass % or more and 3.0 mass % or less, Mn in an amount of 1.0 mass % or more and 3.5 mass % or less, and C in an amount of 0.03 mass % or more to Fe-based electroplating to obtain a pre-annealing Fe-based electroplated steel sheet with a pre-annealing Fe-based electroplating layer formed on at least one surface thereof with a coating weight per surface of 5.0 g/m2 or more;
then heating the pre-annealing Fe-based electroplated steel sheet with an average heating rate of 10° C./sec or higher in a temperature range from 400° C. to 650° C., wherein the heating is not oxidation heating, and cooling the pre-annealing Fe-based electroplated steel sheet after being held in the temperature range in an atmosphere with a dew point above −30° C., to obtain an Fe-based electroplated steel sheet, and
wherein a coating weight (g/m2) per surface of the pre-annealing Fe-based electroplating layer, denoted by C.W.Fe0, and the dew point, denoted by D.P., satisfy the following formula (2):
(C.W.Fe0)+(D.P.)≥15  (2).