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Aluminum

5083-H116

5083-H116 is a high-magnesium marine aluminum alloy with exceptional saltwater corrosion resistance and excellent weldability, retaining strength in the as-welded condition. At 2.66 g/cm3 with 317 MPa tensile and 228 MPa yield, it is the standard for marine hull plate and weldments where corrosion resistance and weld integrity outrank machinability.

How 5083-H116 machines

As a soft, gummy non-heat-treatable alloy, 5083 machines at only 3.0/5, tending to build up on edges and produce stringy chips. Use sharp tools, positive rake, generous coolant, and high speeds to shear cleanly. It is not a free-machining choice; expect more careful tooling than with 6061 or 6082 structural grades.

Manufacturing & processing

5083 shines in welding and forming: it keeps high strength after welding, unlike heat-treatable grades that lose temper at the weld, making it ideal for fabricated marine structures. It is supplied as plate and sheet for sheet-metal work, CNC, and forging. Do not bright-anodize it cosmetically; its high magnesium yields dull, inconsistent anodized finishes.

Typical applications

5083 is used for boat hulls, marine bulkheads, pressure vessels, cryogenic tanks, and saltwater-exposed weldments. Its strength retention after welding and outstanding seawater corrosion resistance make it the default for fabricated marine and offshore structures, vehicle armor, and tanks where weld integrity and corrosion life are paramount.

When to choose it

Choose 5083 for welded marine and saltwater structures needing corrosion resistance and post-weld strength. For machined structural parts or extrusions, 6082 or 6061 machine far better and anodize cleanly. Avoid 5083 where bright anodizing or easy machining is the priority. It wins specifically on weldability and seawater corrosion performance.

Suitable surface finishes

Common finishes for 5083-H116: Type II anodizing, chromate/Alodine, powder coating, bead blasting. Use the finish selector →

FAQ

Why is 5083 preferred for welded marine structures?
5083 is non-heat-treatable, so it does not rely on a temper that welding would destroy. It retains most of its strength in the as-welded condition, unlike 6061 or 6082, which soften at the weld. Combined with top-tier seawater corrosion resistance, this makes it ideal for fabricated marine hulls and tanks.
Can I bright-anodize 5083?
Not for cosmetic bright finishes. Its high magnesium content produces dull, hazy, and inconsistent anodized surfaces. 5083 is specified for corrosion resistance and weldability, not decorative anodizing. If a clean bright-anodized appearance is required, choose a lower-magnesium grade like 6061 or 6082 instead.
Is 5083 harder to machine than 6061?
Yes. At 3.0/5 versus 6061's 4.5, 5083 is softer and gummier, building up on tool edges and producing stringy chips. It needs sharp tools, high speeds, and good coolant. For heavily machined parts, 6061 or 6082 are easier; reserve 5083 for its corrosion and welding strengths.

Property values are typical/nominal for early guidance and vary by temper, grade, supplier and heat treatment. Confirm critical specs against a certified datasheet or with an mfgiq engineer.