Marine aluminum sheets are a fast-growing segment in the metal processing industry. Shipbuilders and offshore engineers demand materials that are lightweight, resist rust, and offer high strength in harsh seawater environments. Producing high-quality marine-grade aluminum sheets requires strict technical control, and a supplier's ability to meet these standards shows their real strength in the global market.
We are GNEE, a Chinese marine aluminum sheet supplier. We specialize in producing marine-grade aluminum alloys. We provide stable, certified aluminum plates that meet international shipbuilding standards. Whether you are building small fishing boats, passenger ferries, or large offshore platforms, choosing the right aluminum material is the first step to success.
Why does the shipbuilding industry use 5000 series aluminum plates?
Marine environments destroy standard metals. For a hull to survive decades in seawater, it requires an alloy that forms a dense, self-repairing oxide layer. The 5000-series aluminum uses Magnesium (Mg) as its primary alloying element. When the magnesium content is between 3.0% and 4.9%, the metal achieves the perfect balance of tensile strength, outstanding weldability, and total immunity to seawater corrosion.
Alloys with higher magnesium (like 5083) offer maximum strength for load-bearing hulls. Alloys with lower magnesium (like 5754) offer better bendability for interior cabin structures.
Chemical Composition of 5083 5086 5754 Marine Aluminum Sheets
| Alloy | Magnesium (Mg) | Manganese (Mn) | Silicon (Si) | Iron (Fe) | Copper (Cu) | Zinc (Zn) | Titanium (Ti) |
| 5083 | 4.0 - 4.9 | 0.40 - 1.0 | ≤ 0.40 | ≤ 0.40 | ≤ 0.10 | ≤ 0.25 | ≤ 0.15 |
| 5086 | 3.5 - 4.5 | 0.20 - 0.70 | ≤ 0.40 | ≤ 0.50 | ≤ 0.10 | ≤ 0.25 | ≤ 0.15 |
| 5754 | 2.6 - 3.6 | ≤ 0.50 | ≤ 0.40 | ≤ 0.40 | ≤ 0.10 | ≤ 0.20 | ≤ 0.15 |
Data Note: The high Mg content in 5083 makes it the strongest non-heat-treatable aluminum alloy in commercial use. The addition of Manganese (Mn) refines the grain structure, increasing the yield strength without sacrificing welding performance.
GNEE provides EN 10204 3.1 mill test certificates with every batch. Send us your alloy and size requirements for a quick factory-direct quote today.
Mechanical Properties of 5083 5086 5754 Marine Aluminum Sheets
| Alloy & Temper | Tensile Strength (Rm MPa) | Yield Strength (Rp0.2 MPa) | Elongation (A50 mm %) | Typical Hardness (HB) |
| 5083-H116/H321 | 305 - 385 | ≥ 215 | ≥ 10 | 75 |
| 5086-H116/H321 | 290 - 360 | ≥ 200 | ≥ 10 | 73 |
| 5754-H111 | 190 - 240 | ≥ 80 | ≥ 12 | 45 |
5083-H116 retains nearly 90% of its tensile strength in the heat-affected zone (HAZ) after welding. This is the primary reason it is specified for critical hull bottoms and bulkheads.
What are the differences between the two states, H116 and H321?
Many buyers ask about the difference between H116 and H321. In terms of yield and tensile strength, they are nearly identical. The difference lies in the metallurgical processing and how they handle specific corrosive attacks.
- H116 (Strain Hardened): This temper is specifically engineered to control the precipitation of magnesium along the grain boundaries. By carefully managing the rolling reduction and cooling rates, H116 prevents the magnesium from clumping. This makes H116 highly resistant to exfoliation corrosion (where the metal flakes off in layers). It is the absolute standard for exterior hulls constantly submerged in seawater.
- H321 (Strain Hardened and Stabilized): This temper undergoes a low-temperature thermal treatment after rolling. This stabilization locks the grain structure in place. H321 is highly resistant to stress corrosion cracking (SCC). It is often preferred for structural components that endure continuous dynamic loads and vibrations, such as engine beds and deck mounts.
To guarantee these properties, GNEE tests both tempers according to ASTM G66 (ASSET test) for exfoliation resistance and ASTM G67 (NAMLT test) for intergranular corrosion.
Unsure whether H116 or H321 is better for your hull design? Our metallurgical engineers can help. Email your structural blueprints to GNEE for free technical consultation and a material pricing estimate.
Parameters Of Marine Grade Aluminum Plate
|
Alloy |
5052 5083 5754 6061 | ||||
|
Temper |
Soft HO, H12, H13, H14, H15, H16, H18, H19, H20, H111, H112, H114, H116, etc | ||||
|
Size |
4x8 aluminum sheet, 4x10 aluminum sheet, 5x10 aluminum sheet | ||||
|
Thickness |
2mm, 2.5mm, 3mm, 3.5mm, 4mm, 5mm, 6mm, 10mm ( thick ), etc | ||||
| Width(mm) | 100-2650 | ||||
|
Length(mm) |
500-16000 |
||||
Practical Shipyard Applications and Thickness Data
1. The Main Hull and Bottom Plates (5083-H116)
The bottom of the boat takes the hardest impact from waves and floating debris, and it sits in saltwater 100% of the time.
Recommended Material: 5083-H116 Marine Aluminum Plate.
Typical Thickness:
Small workboats (10m - 15m): 6mm to 8mm.
Passenger ferries (20m - 30m): 10mm to 12mm.
Large patrol vessels and yachts: 12mm to 20mm.
2. Side Panels and Superstructures (5086-H116)
The sides of the ship need high strength but slightly less extreme pressure resistance than the bottom. 5086 is easier to form into the curved shapes of a modern bow.
Recommended Material: 5086-H116.
Typical Thickness: 4mm to 8mm.
3. Interior Cabin Walls and Consoles (5754-H111)
For the interior structure above the waterline, corrosion is less of a factor, and weight reduction is the main goal. 5754-H111 bends easily in a press brake up to 90 degrees without cracking, making it perfect for custom cabin designs, stairways, and flooring panels.
Recommended Material: 5754-H111 or 5754-O.
Typical Thickness: 3mm to 5mm.
Welding Marine Aluminum
A hull is only as strong as its welds. 5xxx series aluminum cannot be welded with just any wire.
For 5083 and 5086: You must use ER5183 or ER5356 welding wire.
Gas: 100% pure Argon (for plates up to 12mm) or an Argon/Helium mix (for plates over 12mm to increase weld penetration).
Method: MIG (GMAW) is standard for long hull seams. TIG (GTAW) is used for detailed pipe fittings or tight corners.
GNEE's marine aluminum plates feature exceptional surface cleanliness. We remove all rolling oils and oxides before packaging, ensuring your welders do not spend hours grinding the plates before they can strike an arc. Porosity in the weld seam is drastically reduced.
Want to cut down on welding time? We supply wide marine aluminum plates up to 2650mm and extra-long plates up to 12,000mm. Send us your dimensions to see how much fabrication time you can save.
Manufacturing Tolerances (EN 485-3 / ASTM B209)
Standard Tolerance Data for Medium Plates (6 mm – 12 mm Thickness)
| Parameter | Tolerance Standard |
|---|---|
| Thickness Tolerance | ±0.15 mm to ±0.25 mm (with strict control on negative deviation to ensure hull strength compliance with classification society requirements) |
| Width Tolerance | +2.0 mm / -0.0 mm |
| Length Tolerance | +3.0 mm / -0.0 mm |
| Flatness (Waviness) | ≤ 3.0 mm per 1000 mm |
| Diagonal Difference | ≤ 4.0 mm |
GNEE's strict tolerance control helps shipbuilders reduce welding difficulty, improve assembly efficiency, and ensure long-term structural reliability in marine applications.
Marine Classification Certifications
GNEE supplies plates with EN 10204 3.2 certification.
Available Class Approvals:
DNV (Det Norske Veritas - Norway)
ABS (American Bureau of Shipping - USA)
CCS (China Classification Society)
LR (Lloyd's Register - UK)
BV (Bureau Veritas - France)
Contact our sales team for certified marine aluminum pricing
Aluminum vs Shipbuilding Steel
| Property | 5083 Marine Aluminum | Shipbuilding Steel (AH36 / Mild Steel) |
|---|---|---|
| Density (kg/m³) | ~2,660 | ~7,850 |
| Weight Reduction | ~65% lighter than steel | Baseline |
| Tensile Strength (MPa) | 305 – 385 (H116) | 400 – 550 |
| Yield Strength (MPa) | ≥215 | ≥235 |
| Elastic Modulus (GPa) | ~70 | ~200 |
| Corrosion Rate (Seawater) | Very low (natural oxide layer) | High (requires coating) |
| Maintenance Cost (€/m²/year) | ~1 – 3 | ~8 – 15 |
| Welding Efficiency | High (no preheating required) | Medium (preheating often required) |
| Thermal Conductivity (W/m·K) | ~121 | ~50 |
| Fatigue Resistance | Excellent in marine environment | Moderate (corrosion fatigue risk) |
| Lifecycle (Years) | 20 – 30+ | 15 – 25 (with maintenance) |
| Lifecycle Cost Index | ~0.7 – 0.85 | 1.0 (baseline) |
Key Engineering Insights
- Weight Advantage: Aluminum reduces vessel weight by approximately 60–65%, improving fuel efficiency and payload capacity.
- Corrosion Resistance: 5083 aluminum forms a natural oxide layer, eliminating the need for heavy anti-corrosion coatings required for steel.
- Maintenance Savings: Aluminum structures can reduce maintenance costs by up to 50–70% over the vessel lifecycle.
- Structural Consideration: Steel has higher stiffness (elastic modulus), so aluminum designs require optimized structural reinforcement.
GNEE Pricing Formula:
Cost = Base Ingot Price (SMM) + Factory Processing Fee + Classification Certification Fee + Logistics
- Base Ingot Price: GNEE uses the Shanghai Metals Market (SMM) A00 aluminum price as the daily baseline.
- Processing Fee: This covers the cost of adding magnesium, hot rolling, cold rolling, and the H116/H321 thermal treatment. For 5083 marine plates, the processing fee is naturally higher than standard 1000-series aluminum due to the complex metallurgy and extreme energy required for hot rolling high-magnesium blocks.
- Certification Fee: If you require DNV or ABS 3.2 certificates, the classification society charges an inspection fee per batch/tonnage.
- Logistics: Inland transport to the port and ocean freight (FOB/CIF terms).
Cost Control Tip: Standard sizes (e.g., 2000mm x 6000mm) run on continuous production schedules and carry lower processing fees. Custom odd sizes require stopping the line and have higher Minimum Order Quantities (MOQs).
To secure your profit margins, you need accurate, real-time data. Send us your estimated purchase volume and destination port, and GNEE will provide a comprehensive CIF price breakdown within 24 hours.
Export Packaging
GNEE uses strict marine-grade export packaging:
- Interleaving: We apply a protective PVC film to the surface of each plate, or we use pH-neutral interleaving paper between every sheet to prevent friction and moisture trapping.
- Moisture Barrier: The entire stack is wrapped in thick waterproof kraft paper and sealed in heavy-duty plastic.
- Desiccants: We place industrial silica gel bags inside the packaging to absorb any trapped humidity.
- Pallets: The stack is strapped securely to fumigated wooden pallets designed to support 2 to 3 tons per bundle, ensuring safe forklift handling at your dock.
