Surface-treated steel sheet and method of producing same
AssigneeJfe Steel Corporation
InventorsTakashi UENO, Yusuke NAKAGAWA
Life of this patent
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Abstract
A surface-treated steel sheet that can be produced without the use of hexavalent chromium and that combines excellent sulfide staining resistance, paint secondary adhesion, and appearance is provided. A surface-treated steel sheet having, on at least one surface of a steel sheet, a Sn plating layer and a coating layer disposed on the Sn plating layer and containing at least one of Zr oxide or Ti oxide, wherein a water contact angle is 50° or less, and a total atomic ratio of K, Na, Mg, and Ca adsorbed on a surface of the steel sheet to all elements is 5.0% or less.
Claims9
A surface-treated steel sheet comprising, on at least one side of a steel sheet,
- a Sn plating layer;
- and
- a coating layer disposed on the Sn plating layer and containing at least one of Zr oxide and Ti oxide, wherein
- a water contact angle is 50° or less, and
- a total atomic ratio of K, Na, Mg, and Ca adsorbed on a surface of the steel sheet to all elements is 5.0% or less.
A method of producing a surface-treated steel sheet including, on at least one side of a steel sheet, a Sn plating layer, and a coating layer disposed on the Sn plating layer and containing at least one of Zr oxide and Ti oxide, the method comprising:
- a coating formation process of treating a surface of a steel sheet having a Sn plating layer on at least one side with an aqueous solution containing at least one of Zr ions and Ti ions to form the coating layer on the Sn plating layer;
- a surface conditioning process of holding the aqueous solution at over 30.0 g/m2 to 60.0 g/m2 or less on a surface of the coating layer for 0.1 seconds to 20.0 seconds;
- and
- a water washing process of subjecting the steel sheet after the surface conditioning process to water washing at least once, wherein
- in the water washing process,
- water with an electrical conductivity of 100 μS/m or less is used at least in the last water washing.
Dependencies are inferred from the claim text.