Marine grade aluminum alloys generally refer to aluminum alloys used in ships, offshore platforms, offshore engineering and other fields under the conditions of the marine environment. These aluminum alloys are usually approved by classification societies and meet specific standards and requirements for the construction of ships and their related equipment to meet the needs of ships in the marine environment. Marine grade aluminum alloy include seawater-resistant aluminum alloy plates, profiles (including rods and tubes), aluminum alloy rivets, and aluminum alloy pistons for use in ship hulls and equipment. According to different alloy compositions and applications, marine grade aluminum alloy can be divided into various types, such as aluminum-magnesium alloys, aluminum-magnesium-silicon alloys and aluminum-zinc-magnesium alloys.

Common marine grade aluminum alloys include:

1. 5000 series marine grade aluminum alloys: such as 5052, 5059, 5083, 5086, 5383, 5456, 5754, etc., with excellent corrosion resistance and high strength, commonly used in hulls, plates, ship structures and other parts.

2. 6000 series marine grade aluminum alloy: such as 6061, 6063, etc., with good processability and welding performance, suitable for marine platforms, marine equipment, structural components and connectors.

3. 7000 series marine grade aluminum alloys: such as 7075, etc., with high strength and hardness, suitable for high requirements in the field of marine engineering parts, such as submarine pipelines, marine platform support structure.

These marine grade aluminum alloys have good corrosion resistance, light weight, high strength, etc., and are suitable for a variety of projects and equipment in the marine environment.

Performance characteristics of marine grade aluminum alloy are:

- Corrosion resistance: marine grade aluminum alloy has excellent seawater corrosion resistance and can be used for a long time without damage in the harsh marine environment.

- Light weight and high strength: Aluminum alloy has low density but high strength, so marine-grade aluminum alloy can reduce the overall weight of the ship and improve the ship's speed and fuel efficiency while ensuring the strength of the ship's structure.

- Good processing performance: Marine grade aluminum alloy has good plastic processing and welding performance, which is easy to be processed into various shapes and sizes of components to meet the needs of shipbuilding.

Marine grade aluminum alloy is widely used in the field of shipbuilding, including hull structure, superstructure, deck structural parts, cabin structural parts, and shell structural parts of important auxiliary engines. In addition, marine-grade aluminum alloy is also used in the manufacture of cryogenic liquefied gas transportation ball tanks and other special equipment to meet the needs of ships in special working conditions.

The production and use of marine grade aluminum alloy need to be approved by classification societies. Classification society is an organization engaged in class inspection and technical appraisal of ships. The certification of marine grade aluminum alloy including CCS, DBV, LR, BV, KR, ABS, RINA and so on. Through strict examination and testing of the composition, performance and production process of aluminum alloy materials, it ensures that the ship-grade aluminum alloy meets the relevant standards and requirements. Only the aluminum alloy materials approved by classification societies can be used in the field of shipbuilding.

With the continuous development of shipbuilding technology and the increasing requirement of environmental protection, the application prospect of marine grade aluminum alloy in the field of shipbuilding is getting broader and broader. In the future, marine-grade aluminum alloy will pay more attention to the research and development and application of light weight, high strength, corrosion resistance and environmental protection to meet the demand for high-performance materials in shipbuilding field.

In summary, marine grade aluminum alloy is one of the important materials in the field of shipbuilding, with excellent corrosion resistance, light weight and high strength and good processing performance. With the continuous progress of technology and the improvement of environmental protection requirements, the application prospect of marine grade aluminum alloy will be broader.