Method for producing black-plated steel sheet, and method for producing molded article of black-plated steel sheet

Patent metadata

Field	Value
Publication number	US-9598773-B2
Application number	US-201314396210-A
Country	US
Kind code	B2
Filing date	Apr 23, 2013
Priority date	Apr 25, 2012
Publication date	Mar 21, 2017
Grant date	Mar 21, 2017

Abstract

The present invention pertains to a method for producing a black-plated steel sheet capable of being blackened in a short amount of time, and exhibiting an excellent ability to maintain a black appearance after processing. As an original sheet, the sheet used is a Zn-plating steel sheet which contains molten Al and Mg and has a Zn-plating layer containing molten Al and Mg, containing Al in the amount of 1.0-22.0 mass %, inclusive, and containing Mg in the amount of 1.5-10.0 mass %, inclusive. The plating layer is blackened by causing the molten-plating steel sheet to contact water vapor inside a tightly sealed container. When doing so, the concentration of oxygen inside the tightly sealed container is 13% or less.

First claim

The invention claimed is:

1. A method for producing a black-plated steel sheet, comprising:
reducing an oxygen concentration in a closed vessel to 13% or less by replacing air in the closed vessel with an inert gas or removing the air in the closed vessel;
providing a hot-dip Al and Mg-containing Zn-plated steel sheet comprising a hot-dip Al and Mg-containing Zn-plated layer which comprises 1.0 mass % or more and 22.0 mass % or less of Al, and 1.5 mass % or more and 10.0 mass % or less of Mg; and
contacting the hot-dip Al and Mg-containing Zn-plated steel sheet with water vapor in the closed vessel.

2. The method for producing a black-plated steel sheet according to claim 1 , further comprising forming an inorganic coating film on a surface of the hot-dip Al and Mg-containing Zn-plated steel sheet.

3. The method for producing a black-plated steel sheet according to claim 2 , wherein the inorganic coating film comprises one or more compounds selected from the group consisting of an oxide of valve metal, an oxoate of valve metal, a hydroxide of valve metal, a phosphate of valve metal, and a fluoride of valve metal, and
the valve metal is one or more metals selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, W, Si and Al.

4. The method for producing a black-plated steel sheet according to claim 1 , further comprising forming an organic resin coating film on a surface of the hot-dip Al and Mg-containing Zn-plated steel sheet.

5. The method for producing a black-plated steel sheet according to claim 4 , wherein:
an organic resin comprised in the organic resin coating film is urethane-based resin obtained by reaction of polyols consisting of an ether-based polyol and an ester-based polyol with polyisocyanate, and
a proportion of the ether-based polyol in the polyols being 5 to 30 mass %.

6. The method for producing a black-plated steel sheet according to claim 5 , wherein the organic resin coating film further comprises a polyvalent phenol.

7. The method for producing a black-plated steel sheet according to claim 4 , wherein the organic resin coating film comprises a lubricant.

8. The method for producing a black-plated steel sheet according to claim 4 , wherein the organic resin coating film comprises one or more compounds selected from the group consisting of an oxide of valve metal, an oxoate of valve metal, a hydroxide of valve metal, a phosphate of valve metal, and a fluoride of valve metal, and
the valve metal is one or more metals selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, W, Si and Al.

9. The method for producing a black-plated steel sheet according to claim 4 , wherein the organic resin coating film is a laminate layer or a coating layer.

10. The method for producing a black-plated steel sheet according to claim 4 , wherein the organic resin coating film is a clear coating film.

11. A method for producing a formed article of a black-plated steel sheet, comprising:
reducing an oxygen concentration in a closed vessel to 13% or less by replacing air in the closed vessel with an inert gas or removing the air in the closed vessel;
providing a hot-dip Al and Mg-containing Zn-plated steel sheet comprising a hot-dip Al and Mg-containing Zn-plated layer which comprises 1.0 mass % or more and 22.0 mass % or less of Al, and 1.5 mass % or more and 10.0 mass % or less of Mg;
contacting the hot-dip Al and Mg-containing Zn-plated steel sheet with water vapor in the closed vessel; and
forming the hot-dip Al and Mg-containing Zn-plated steel sheet into an article.

Assignees

• Nisshin Steel Co Ltd

Inventors

• Nakano Tadashi
• Yamamoto Masaya
• Taketsu Hirofumi

Classifications

• C23C2/06 Primary

  Zinc or cadmium or alloys based thereon · CPC title

• C23C28/3225

  with at least one zinc-based layer · CPC title

• C22C38/00

  Ferrous alloys, e.g. steel alloys (cast-iron alloys C22C37/00) · CPC title

• C23C2/12

  Aluminium or alloys based thereon · CPC title

• C23C8/02

  Pretreatment of the material to be coated (C23C8/04 takes precedence) · CPC title