Gold-colored steel sheet and manufacturing method thereof

Patent metadata

Field	Value
Publication number	US-11339459-B2
Application number	US-201716473030-A
Country	US
Kind code	B2
Filing date	May 15, 2017
Priority date	Dec 23, 2016
Publication date	May 24, 2022
Grant date	May 24, 2022

Abstract

The present invention discloses a gold-colored steel sheet capable of expressing color without peeling of a modified layer and the gold-colored steel sheet capable of forming a color-modified layer through a conventional annealing process without expensive facilities.A method of manufacturing the gold-colored steel sheet according to an embodiment of the present invention can form a TiN modified layer on a surface of a steel sheet comprising 0.3 to 1.5 wt % of titanium (Ti) by an annealing treatment in a nitrogen (N2) atmosphere at 900 to 1,200° C. for 30 to 300 seconds.

First claim

The invention claimed is:

1. A gold-colored steel sheet comprising a base material and a modified layer provided on an outermost surface layer of the base material,
wherein the modified layer is a TiN modified layer comprising 30 wt % or more of Ti and 10 wt % or more of N,
wherein the TiN modified layer has a thickness of 20 to 120 nm, and
wherein alloy element contents in the TiN modified layer satisfy the following formula (1):
0.1 wt %≤C+Si+Al+Mn+Cr+Ni+Nb+Zr≤35.0 wt %  (1)

here, C, Si, Al, Mn, Cr, Ni, Nb and Zr mean the content (wt %) of each element.

2. The gold-colored steel sheet according to claim 1 , wherein a b* value of an L*a*b* color system of a surface of the TiN modified layer is 25 or more.

3. The gold-colored steel sheet according to claim 1 , wherein the base material comprises 0.003 wt % or less of N and 0.015 wt % or less of C+N.

4. The gold-colored steel sheet according to claim 1 , wherein the content of Ti in the TiN modified layer diffused from the base material thereby reducing the content of Ti in the base material.

5. The gold-colored steel sheet according to claim 4 , wherein the TiN modified layer has a thickness of 65 to 75 nm.

6. The gold-colored steel sheet according to claim 1 , wherein the gold-colored steel sheet has a pitting potential of 300 mV or more.

Assignees

• Posco

Inventors

• Kong Jung-Hyun
• Kim Sang Seok
• Park Mi Nam

Classifications

• C22C38/02

  containing silicon · CPC title

• C22C38/04

  containing manganese · CPC title

• C21D8/0257

  with diffusion of elements, e.g. decarburising, nitriding · CPC title

• C21D3/08

  Extraction of nitrogen · CPC title

• C21D2201/00

  Treatment for obtaining particular effects · CPC title