Selection summary
Overview
5083 is a high-magnesium aluminum alloy used in marine, transportation, cryogenic, and welded plate applications. Marine performance is tied to temper and product controls such as H116 or H321, not to the 5083 designation alone.
This page separates standard-oriented limits from typical reference data. Purchase acceptance comes from the ordered specification and certified material test report.
Names and systems
Identity & standards
Similar designations across ASTM, EN, JIS, and other systems are not automatically interchangeable. Product form and ordered standard control chemistry, properties, dimensions, condition, and testing.
Reference chemistry
Composition
| Element | Reference range | Why it matters |
|---|---|---|
| Magnesium | 4.0–4.9% | Strength and marine corrosion performance |
| Manganese | 0.40–1.0% | Strength and structure control |
| Chromium | 0.05–0.25% | Structure and corrosion behavior |
Concise grade-family reference only. Confirm every element limit against the current standard for the exact product ordered.
Condition matters
Reference properties
H116/H321 marine plate minimums vary with product and thickness
Use the governing plate standard and certified temper results
Typical room-temperature reference value
Environment first
Corrosion behavior
Widely used for seawater and marine structures when correct temper, design, and fabrication are maintained.
Prolonged exposure in sensitizing temperature ranges can harm intergranular-corrosion performance in high-magnesium 5xxx alloys.
Temperature, concentration, deposits, crevices, stress, surface finish, cleaning, and fabrication quality can change service performance.
Service limits
Temperature & service
Review sensitization limits before sustained elevated-temperature service.
Delivery condition
Heat treatment & condition
5083 is non-heat-treatable and obtains strength from magnesium solid-solution strengthening and strain hardening; H116/H321 are corrosion-performance-controlled marine tempers, not generic hardness labels.
Sustained exposure in sensitizing temperature ranges can precipitate magnesium-rich phases at grain boundaries, so service temperature and fabrication heat history require control.
Process route
Fabrication
Good weldability, but heat-affected-zone strength is lower than parent temper values.
Control filler, joint design, distortion, plate temper, and marine inspection requirements.
Magnetic response: Non-ferromagnetic.
Decision boundaries
Comparisons & substitution
Compared with 5052, 5083 offers higher strength and established marine-plate routes but requires stricter high-magnesium temper and sensitization control.
6061 provides heat-treatable strength and broad extrusion availability, while welded 5083 is often selected for marine plate where postweld solution treatment is impractical.
Where it is used
Applications
Ordering scope
Product forms & standards
Marine plate and sheet in H116 or H321 under ASTM B928/B928M or the specified classification-society rules when their corrosion testing is required.
General sheet/plate, extrusions, bars, tube, and forgings require their own applicable product standards and registered tempers.
State alloy, exact temper, thickness, test orientation, exfoliation/intergranular-corrosion tests, class approval, flatness, and ultrasonic requirements.
Decision support
Selection guidance
Choose this grade when
- Welded marine plate needs a strong, corrosion-resistant non-heat-treatable alloy.
- The purchase can specify H116/H321 and applicable marine or class requirements.
Review another grade when
- Complex extrusions or peak heat-treated strength are the primary need.
- Service includes sustained temperatures that can sensitize high-magnesium 5xxx material.
Before ordering
Procurement checklist
State alloy, temper, product specification, dimensions, tolerances, surface finish, edge, and quantity.
Require heat or lot traceability and a certificate showing chemistry, temper, mechanical tests, and ordered inspection.
Confirm fabrication, welding, anodizing or coating, flatness, residual-stress condition, packaging, destination, and delivery target.
State marine temper, classification-society approval, corrosion tests, weld procedure, plate flatness, and ultrasonic requirements.
Traceable evidence