Gold-colored steel sheet and manufacturing method thereof
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 (N 2 ) atmosphere at 900 to 1,200° C. for 30 to 300 seconds.
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.