HIGHLY CORROSION-RESISTANT HOT DIP GALVANIZED STEEL STOCK

摘要

A highly corrosion-resistant hot dip galvanized steel stock that attains not only an enhancement of corrosion resistance of galvanized layer per se by additive element but also workability free from deterioration attributed to formation of intermetallic compound by additive element or sacrificial corrosion resistance performance of galvanized layer for base metal. There is provided a highly corrosion-resistant hot dip galvanized steel stock characterized by having an alloy plated layer of 35 mass% or more, preferably 40 mass% or more, Zn content containing a nonequilibrium phase of 1 J/g or more calorific value as determined by differential scanning calorimetry. It is preferred that an amorphous phase of 5% or more, preferably 50% or more, volume fraction be contained. The alloy layer contains, by mass, 1 to 60% Mg and 0.07 to 59% Al. Further, the alloy layer may contain 0.1 to 10% total of at least one member selected from among Cr, Mn, Fe, Co, Ni and Cu. Also, there may be contained at least one member selected from among 0.1 to 10% La, 0.1 to 10% Ce, 0.1 to 10% Ca, 0.1 to 10% Sn, 0.005 to 2% P and 0.02 to 7% Si.