Aluminum 5000 series (5xxx) alloys are commonly used for ship structures. The alloys with > 3% Mg have problems with sensitization, collection of the B-phase (Mg2Al3) at grain boundaries when exposed to elevated temperatures. The corrosion mode of many sensitized alloys is exfoliation, while non-sensitized alloys tend to pit. This study attempts to find correlation of corrosion mode to cyclic polarization data by comparison with ASTM G66 and ASTM G67 accelerated tests data.