High-corrosion-resistance hot-dip galvanized steel sheet having excellent appearance uniformity and manufacturing method thereof

摘要

The present invention provides a high-corrosion-resistance hot-dip galvanized steel sheet having excellent appearance uniformity. The steel sheet includes: a coating layer containing Al: 4 to 22 mass %, Mg: 1 to 6 mass %, and Si: 0.001 to 1 mass %, and a balance being composed of Zn and inevitable impurities formed on a surface, in which at an interface between the coating layer and a base steel sheet, Mg2Si phases and Ca phases each mainly composed of Ca or a Ca compound exist, and at least part of the Mg2Si phases precipitate by using the Ca phases as a nucleus.

主权项

1. A high-corrosion-resistance hot-dip galvanized steel sheet having excellent appearance uniformity, comprising:
a coating layer containing Al: 4 to 22 mass %, Mg: 1 to 6 mass %, and Si: 0.001 to 1 mass %, and a balance being composed of Zn and inevitable impurities formed on a surface, wherein at an interface between said coating layer and a base steel sheet, Mg2Si phases and Ca phases each mainly composed of Ca or a Ca compound exist, and at least part of the Mg2Si phases precipitate by using the Ca phases as a nucleus, an average diameter of Al/MgZn2/Zn ternary eutectic phases existing in said coating layer is 5 to 200 μm, and an interface Ca intensity at the interface between said coating layer and the base steel sheet is 0.1 to 1.0.