ALLOYED HOT-DIP GALVANIZED STEEL SHEET HAVING EXCELLENT FORMABILITY AND POST-ADHESION DETACHMENT RESISTANCE, AND MANUFACTURING METHOD THEREFOR.

摘要

Disclosed is an alloyed hot-dip galvanized steel sheet provided with: a steel sheet; an alloyed hot-dip galvanization layer that is formed on at least one surface of the steel sheet and contains between 0.05% and 0.5% aluminum and between 6% and 12% iron, by mass, with the remainder comprising zinc and unavoidable impurities; and a mixed layer that is formed on the surface of the alloyed hot-dip galvanization layer and contains a magnesium/zinc/phosphorus complex oxide and a water-soluble phosphorus compound. The complex oxide contains between 0.1 mg/m² and 100 mg/m² magnesium, between 1 mg/m² and 100 mg/m² phosphorus, and zinc. The ratio between the amount of phosphorus and the amount of magnesium in the complex oxide is between 0.3 and 50. The total area of regions of the mixed layer that have at least 20 mg/m² of adhered phosphorus is between 20% and 80% of the total surface area of the mixed layer.