About 5083|The strongest non-heat-treatable aluminum. Excellent corrosion resistance, especially in seawater. This is the hull plate alloy for high-performance marine vessels and the standard for cryogenic tanks and pressure vessels. Machines better than you’d expect for a 5xxx alloy — the higher magnesium content (4.0–4.9%) gives it more body than
5052, so chips break a bit cleaner. Still gummier than
6061. Welds well with 5356 filler. About 10–15% stronger than
5086. If you’re building anything that needs to survive saltwater and structural loading simultaneously, 5083 is likely on the drawing. Compare to 5086 (slightly weaker, otherwise similar) and 6061 (heat-treatable, better machinability, less marine corrosion resistance).