US 11,939,692 B2
Steel sheet for can making and method for manufacturing the same
Yusuke Nakagawa, Tokyo (JP); Hanyou Sou, Tokyo (JP); and Yoichiro Yamanaka, Tokyo (JP)
Assigned to JFE STEEL CORPORATION, Tokyo (JP)
Appl. No. 17/271,967
Filed by JFE STEEL CORPORATION, Tokyo (JP)
PCT Filed Jun. 7, 2019, PCT No. PCT/JP2019/022692
§ 371(c)(1), (2) Date Feb. 26, 2021,
PCT Pub. No. WO2020/044714, PCT Pub. Date Mar. 5, 2020.
Claims priority of application No. 2018-159831 (JP), filed on Aug. 29, 2018.
Prior Publication US 2021/0324532 A1, Oct. 21, 2021
Int. Cl. C25D 5/18 (2006.01); C25D 3/08 (2006.01); C25D 3/12 (2006.01); C25D 5/00 (2006.01); C25D 5/12 (2006.01); C25D 5/14 (2006.01); C25D 5/36 (2006.01); C25D 5/50 (2006.01); C25D 9/06 (2006.01); C25D 9/10 (2006.01); C25D 11/38 (2006.01)
CPC C25D 5/18 (2013.01) [C25D 3/08 (2013.01); C25D 3/12 (2013.01); C25D 5/12 (2013.01); C25D 5/14 (2013.01); C25D 5/36 (2013.01); C25D 5/50 (2013.01); C25D 5/605 (2020.08); C25D 5/617 (2020.08); C25D 5/627 (2020.08); C25D 9/06 (2013.01); C25D 9/10 (2013.01); C25D 11/38 (2013.01); Y10T 428/12611 (2015.01)] 1 Claim
OG exemplary drawing
 
1. A steel sheet for can making, comprising an iron nickel diffusion layer, a metallic chromium layer, and a chromium oxide layer on at least one surface of the steel sheet in order from a steel sheet side,
wherein the iron nickel diffusion layer has a nickel coating weight in a range of 50 mg/m2 to 500 mg/m2 per surface of the steel sheet and a thickness in a range of 0.060 μm to 0.500 μm per surface of the steel sheet,
the metallic chromium layer includes a flat metallic chromium sublayer and a granular metallic chromium sublayer placed on a surface of the flat metallic chromium sublayer, a total chromium coating weight of both sublayers per surface of the steel sheet is in a range of 60 mg/m2 to 200 mg/m2, the granular metallic chromium sublayer including granular protrusions having a number density in a range of 5 μm−2 or more per unit area and a maximum diameter of 150 nm or less,
the chromium oxide layer has a chromium coating weight in a range of 3 mg/m2 to 10 mg/m2 per surface of the steel sheet in terms of metallic chromium, and
a rust area fraction of the steel sheet is less than 5%, the rust area fraction of the steel sheet being measured by:
Erichsen-forming a sample taken from the steel sheet at an indentation depth of 4 mm,
then aging the sample for seven days in a constant-temperature, constant-humidity chamber with a temperature of 40° C. and a relative humidity of 80%, and
then determining the rust area fraction of the steel sheet from a photograph obtained by observing an Erichsen-formed portion with an optical microscope at low magnification by image analysis.