US 12,305,286 B2
Metal sheet treatment method and metal sheet treated with this method
Frida Gilbert, Antony (FR); Lydia Rachiele, Rombas (FR); Delphine Thai, Bousse (FR); and Christian Allely, Metz (FR)
Assigned to ArcelorMittal, Luxembourg (LU)
Appl. No. 17/768,009
Filed by ArcelorMittal, Luxembourg (LU)
PCT Filed Oct. 12, 2020, PCT No. PCT/IB2020/059548
§ 371(c)(1), (2) Date Apr. 11, 2022,
PCT Pub. No. WO2021/074765, PCT Pub. Date Apr. 22, 2021.
Prior Publication US 2024/0093375 A1, Mar. 21, 2024
Int. Cl. C23C 2/26 (2006.01); C23C 22/53 (2006.01); C23C 22/82 (2006.01); C23C 28/00 (2006.01)
CPC C23C 2/26 (2013.01) [C23C 22/53 (2013.01); C23C 22/82 (2013.01); C23C 28/3225 (2013.01); C23C 28/34 (2013.01)] 16 Claims
OG exemplary drawing
 
1. A coated steel comprising:
a steel substrate; and
a metallic coating, the steel substrate coated on at least one face with the metallic coating, the metallic coating based on zinc or a zinc alloy wherein the metallic coating is itself coated with a conversion layer comprising:
zincsulphate hydrate,
aluminium, wherein aluminum is present in an amount of no more than 14 mg·m−2,
 wherein the conversion layer comprises neither zinc hydroxysulphate, nor free water molecules nor any compounds having free hydroxyl groups, a surface density of sulphur in the conversion layer being greater than or equal to 5.0 mg/m2.