Surface-treated steel sheet

Patent metadata

Field	Value
Publication number	US-12331408-B2
Application number	US-202218841582-A
Country	US
Kind code	B2
Filing date	Sep 28, 2022
Priority date	Mar 3, 2022
Publication date	Jun 17, 2025
Grant date	Jun 17, 2025

Abstract

A surface-treated steel sheet includes: a base steel sheet; a plated layer formed on the base steel sheet and containing 50 mass % or more of Zn and 0.3 mass % or more of Mg; and a chemical conversion coating formed on the plated layer. The chemical conversion coating contains a silicon compound, P and F, and Mg, an average Si concentration of the chemical conversion coating is 10 mass % or more, the chemical conversion coating includes an F—Mg concentrated layer having an Mg concentration of 1.50 mass % or more and 40.00 mass % or less and an F concentration of 0.50 mass % or more and 5.00 mass % or less in a region in contact with an interface between the chemical conversion coating and the plated layer, a thickness of the F—Mg concentrated layer is 1.0 nm or more, and an average Mg concentration is less than 0.50 mass % and an average F concentration is less than 0.50 mass % in a region of the chemical conversion coating excluding the F—Mg concentrated layer.

First claim

What is claimed is:

1. A surface-treated steel sheet, comprising:
a base steel sheet;
a plated layer formed on the base steel sheet and containing 50 mass % or more of Zn and 0.3 mass % or more of Mg; and
a chemical conversion coating formed on the plated layer,
wherein the chemical conversion coating contains a silicon compound, P and F, and Mg,
an average Si concentration of the chemical conversion coating is 10 mass % or more,
the chemical conversion coating includes an F—Mg concentrated layer having an Mg concentration of 1.50 mass % or more and 40.00 mass % or less and an F concentration of 0.50 mass % or more and 5.00 mass % or less in a region in contact with an interface between the chemical conversion coating and the plated layer,
a thickness of the F—Mg concentrated layer is 1.0 nm or more, and
an average Mg concentration is less than 0.50 mass % and an average F concentration is less than 0.50 mass % in a region of the chemical conversion coating excluding the F—Mg concentrated layer.

2. The surface-treated steel sheet according to claim 1 , wherein
the thickness of the F—Mg concentrated layer is 5.0 nm or more and 100.0 nm or less in the chemical conversion coating.

3. The surface-treated steel sheet according to claim 1 , wherein
a chemical composition of the plated layer includes, in terms of mass %,
Al: 4.0% or more and less than 25.0%,
Mg: 0.3% or more and less than 12.5%,
Sn: 0% or more and 20% or less,
Bi: 0% or more and less than 5.0%,
In: 0% or more and less than 2.0%,
Ca: 0% or more and 3.0% or less,
Y: 0% or more and 0.5% or less,
La: 0% or more and less than 0.5%,
Ce: 0% or more and less than 0.5%,
Si: 0% or more and less than 2.5%,
Cr: 0% or more and less than 0.25%,
Ti: 0% or more and less than 0.25%,
Ni: 0% or more and less than 0.25%,
Co: 0% or more and less than 0.25%,
V: 0% or more and less than 0.25%,
Nb: 0% or more and less than 0.25%,
Cu: 0% or more and less than 0.25%,
Mn: 0% or more and less than 0.25%,
Fe: 0% or more and 5.0% or less,
Sr: 0% or more and less than 0.5%,
Sb: 0% or more and less than 0.5%,
Pb: 0% or more and less than 0.5%,
B: 0% or more and less than 0.5%, and
the remainder: Zn and an impurity.

4. The surface-treated steel sheet according to claim 2 , wherein
a chemical composition of the plated layer includes, in terms of mass %,
Al: 4.0% or more and less than 25.0%,
Mg: 0.3% or more and less than 12.5%,
Sn: 0% or more and 20% or less,
Bi: 0% or more and less than 5.0%,
In: 0% or more and less than 2.0%,
Ca: 0% or more and 3.0% or less,
Y: 0% or more and 0.5% or less,
La: 0% or more and less than 0.5%,
Ce: 0% or more and less than 0.5%,
Si: 0% or more and less than 2.5%,
Cr: 0% or more and less than 0.25%,
Ti: 0% or more and less than 0.25%,
Ni: 0% or more and less than 0.25%,
Co: 0% or more and less than 0.25%,
V: 0% or more and less than 0.25%,
Nb: 0% or more and less than 0.25%,
Cu: 0% or more and less than 0.25%,
Mn: 0% or more and less than 0.25%,
Fe: 0% or more and 5.0% or less,
Sr: 0% or more and less than 0.5%,
Sb: 0% or more and less than 0.5%,
Pb: 0% or more and less than 0.5%,
B: 0% or more and less than 0.5%, and
the remainder: Zn and an impurity.

Assignees

• Nippon Steel Corp

Inventors

• Shimizu Atsuo
• Nishida Yoshikatsu
• Ueno Shin
• Shoji Hiromasa

Classifications

• C23C2222/20

  Use of solutions containing silanes · CPC title

• C23C22/36 Primary

  containing also phosphates · CPC title

• C23C2/06

  Zinc or cadmium or alloys based thereon · CPC title

• C21D9/46

  for sheet metals · CPC title

• C23C2/29

  Cooling or quenching · CPC title