Metallic coated steel
This metallic coated steel includes a steel material and a metallic coating layer. The metallic coating layer has an average chemical composition including Al: 0.2% to less than 4.0%, Mg: more than 4.0% and less than 12.5%, Ca: 0.15% to less than 3.00%, Zn: 65% or more, and impurities. In an any perpendicular cross section (in a thickness direction) in the metallic coating layer, a metallurgical structure observed in a scanning electron microscope observed visual field contains, in terms of area fraction, an MgZn 2 phase: 10 to 40%, an Al—Zn phase: 0 to 15%, an Al phase: (Zn<10%): 0 to 5%, a CaZn 13 phase: 1.0 to 15%, and a total of a [ternary eutectic structure of Al/MgZn 2 /Zn] and a [binary eutectic structure of MgZn 2 /Zn]: 30% or more.
1. A metallic coated steel comprising:
a steel material; and
a metallic coating layer formed on a surface of the steel material,
wherein the metallic coating layer has an average chemical composition including, in terms of mass %,
Al: 0.2% to less than 4.0%,
Mg: more than 4.0% and less than 12.5%,
Ca: 0.15% to less than 3.00%,
Sn: 0% to less than 3.0%,
Bi: 0% to less than 1.0%,
In: 0% to less than 1.0%,
Sc: 0% to less than 0.50%,
Y: 0% to less than 0.50%,
La: 0% to less than 0.50%,
Ce: 0% to less than 0.50%,
Sr: 0% to less than 0.50%,
Si: 0% to less than 2.50%,
B: 0% to less than 0.50%,
P: 0% to less than 0.50%,
Cr: 0% to less than 0.25%,
Ti: 0% to less than 0.25%,
Ni: 0% to less than 1.0%,
Co: 0% to less than 0.25%,
V: 0% to less than 0.25%,
Nb: 0% to less than 0.25%,
Cu: 0% to less than 1.0%,
Mn: 0% to less than 0.25%,
Mo: 0% to less than 0.25%,
W: 0% to less than 0.25%,
Zr: 0% to less than 0.25%,
Fe: 0% to less than 5.0%,
Ag: 0% to less than 1.0%,
Li: 0% to less than 0.50%,
Na: 0% to less than 0.05%,
K: 0% to less than 0.05%,
Sb: 0% to less than 0.5%,
Pb: 0% to less than 0.5%,
Zn: 65% or more, and
impurities, and
in a cross section of the metallic coating layer in a thickness direction, a metallurgical structure observed in a scanning electron microscope observed visual field contains, in terms of area fraction,
an MgZn 2 phase: 10 to 40%,
an Al—Zn phase: 0 to 15%,
an Al phase: 0 to 5%,
a CaZn 13 phase: 1.0 to 15.0%, and
a total of a [ternary eutectic structure of Al/MgZn 2 /Zn] and a [binary eutectic structure of MgZn 2 /Zn]: 30.0% or more.
2. The metallic coated steel according to claim 1 , wherein among the CaZn 13 phases of the metallurgical structure in the cross section of the metallic coating layer in the thickness direction, an average circle-equivalent diameter of top 80% CaZn 13 phases in descending order of circle-equivalent diameter is 10 μm or more.
3. The metallic coated steel according to claim 1 , wherein when a mass concentration % of an element X in the average chemical composition of the metallic coating layer is represented by [X], the average chemical composition of the metallic coating layer satisfies the following formula (1):
2.5×[Al]+2×[Ca]+[Y]+[Sr]+[La]+[Ce]>[Mg] (1).
4. The metallic coated steel according to claim 2 , wherein when a mass concentration % of an element X in the average chemical composition of the metallic coating layer is represented by [X], the average chemical composition of the metallic coating layer satisfies the following formula (1):
2.5×[Al]+2×[Ca]+[Y]+[Sr]+[La]+[Ce]>[Mg] (1).