Aluminum alloys have been used in shipbuilding since 1891. After nearly a century of research and development, their application in marine engineering has expanded significantly, making them one of the most promising materials in the shipbuilding industry.

In the 1930s, 6061-T6 aluminum alloy was introduced and used in riveted ship structures. In the 1940s, weldable and corrosion-resistant Al-Mg alloys were developed. The 1950s saw the adoption of TIG welding technology. In the 1960s, the U.S. Navy developed 5086-H32 and 5456-H321 alloy plates, as well as 5086-H111 and 5456-H111 extrusions. These innovations eliminated grain boundary precipitation networks and solved exfoliation and intergranular corrosion issues—marking a major breakthrough in marine aluminum alloy development.

Why Choose Aluminum Alloys for Shipbuilding?

1. Lightweight

The density of aluminum is only about 34% that of steel. Aluminum structures can reduce vessel weight by 15%–20%, resulting in higher speed, lower fuel consumption, or increased cargo capacity.

2. Excellent Seawater Corrosion Resistance

Seawater is a highly corrosive electrolyte. While steel requires complex coatings and cathodic protection, aluminum alloys naturally resist corrosion. In marine atmospheres, corrosion depth is less than 0.4 μm/year after 8 years of exposure.

3. Good Weldability

Modern ships rely heavily on welded structures. 5000 and 6000 series aluminum alloys can be welded using TIG (GTAW) and MIG (GMAW) processes, ensuring high construction efficiency and structural integrity.

4. Non-Magnetic Properties

Aluminum alloys are non-magnetic, making them ideal for naval vessels such as minesweepers. They also perform well at low temperatures and are easy to fabricate.

Classification System of Marine Aluminum Alloys

Common Tempers of Marine Aluminum Alloys

• O (Annealed): Softest condition, excellent formability

• H111: Slightly strain-hardened, moderate strength

• H112: Strain-hardened after hot rolling without special treatment

• H116: სპეციally treated for marine use with excellent exfoliation corrosion resistance (standard for 5083 plates)

• H321: Stabilized temper, similar to H116, often used for high-Mg alloys like 5456

• T6: Solution heat-treated and artificially aged (typical for 6000 series)

Product Specifications of Marine Aluminum Alloys

Aluminum Plates

Aluminum Extrusions

Application Areas

Classification Society Certifications

Marine aluminum materials must be certified by recognized classification societies, including:

• CCS (China Classification Society)

• DNV (Det Norske Veritas)

• ABS (American Bureau of Shipping)

• LR (Lloyd's Register)

MC Aluminum's 5083 and 5086 plates have obtained relevant certifications and meet international marine standards.

FAQ

Q1: Why is 5083 widely used in shipbuilding?

A: 5083 aluminum offers excellent seawater corrosion resistance, good weldability, high strength, and stability, making it ideal for hull structures and decks.

Q2: Can marine aluminum alloys be welded with regular electrodes?

A: No. Proper aluminum welding wires must be used:

5083/5086 → ER5183 or ER5356

6061/6063 → ER4043 or ER5356

Steel or copper electrodes must NOT be used. Recommended methods include MIG and TIG welding. For large structures, Friction Stir Welding (FSW) is more advanced.

Q3: What is the price of marine aluminum alloys?

A: Prices depend on alloy grade, temper, thickness, certification, and logistics. Typically, marine-grade aluminum is 30%–50% more expensive than standard industrial aluminum.

For example:

5083-H116 (4–10 mm): approx. RMB 25,000–35,000/ton (subject to market fluctuations)

Q4: Can marine aluminum alloys be customized?

A: Yes, customization includes:

Thickness and dimensions

Alloy and temper selection

Surface treatments (anodizing, coating, etc.)

Special performance requirements (high strength, corrosion resistance)