GALVANIZED STEEL SHEET AND PRODUCING 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 magnesium/zinc/phosphorus complex oxide layer that is formed on the surface of the alloyed hot-dip galvanization layer and contains between 0.1 mg/m and 100 mg/m magnesium, between 1 mg/m and 100 mg/m phosphorus, and zinc. The ratio between the amount of phosphorus and the amount of magnesium in the complex oxide layer is between 0.3 and 50. At the interface between the alloyed hot-dip galvanization layer and the complex oxide layer (5), the alloyed hot-dip galvanization layer has a flat region having an area ratio between 10% and 70% and a roughened-surface region that is closer to the steel sheet than the flat region is. The magnesium/zinc/phosphorus complex oxide layer contains an amorphous compound.