There are many alloy grades of aluminum for boats, mainly concentrated in 5000 series and 6000 series aluminum alloys. These alloy states are mostly H111/H112/H321, and common thicknesses are 1mm, 2mm, 3mm, 4mm, 5mm, etc.
5000 series aluminum alloy (Al-Mg series)
500 series aluminum alloy uses magnesium as the main alloying element, has excellent seawater corrosion resistance, weldability and medium-to-high strength, and is the core choice of aluminum sheet for boat building.
1. 5083 Aluminum
- Characteristics: high strength, high corrosion resistance (especially seawater exfoliation corrosion resistance), good weldability and low temperature toughness.
- Application: main hull structure (such as deck, bottom, side plate), superstructure, high-speed boat, patrol boat, warship, etc.
- Typical state: H116, H321 (suitable for marine environment).
2. 5086 Aluminum
- Characteristics: better ductility than 5083 aluminum, outstanding fatigue resistance, slightly inferior to 5083 aluminum in corrosion resistance but better than other 5000 series aluminum grades.
- Application: hull structural parts, pressure vessels, deck coverings, parts requiring high formability.
- Typical state: H32, H34.
3. 5454
Features: medium strength, excellent corrosion resistance and weldability, strong resistance to stress corrosion cracking.
Application: pressure vessels, welded structural parts, offshore platforms, small ships.
Typical state: H321, O (annealed state).
4. 5052
- Features: medium to high strength, good corrosion resistance, processability and anodizing performance.
- Application: non-load-bearing structural parts (such as porthole frames, interior panels), small boats, decorative parts.
- Typical state: H32, H34.
6000 series aluminum alloy (Al-Mg-Si series)
6000 series aluminum alloy forms Mg₂Si strengthening phase by adding magnesium and silicon, has heat treatment strengthening, good processability and corrosion resistance, and is suitable for scenes with medium strength requirements.
1. 6061
- Characteristics: medium strength, good weldability, machinability and corrosion resistance, strength can be improved by T6 heat treatment.
- Application: marine profiles (such as masts, railings), bridges, non-load-bearing structural parts, high-speed boat parts.
- Typical state: T6 (heat treatment strengthening), O (annealing state).
2. 6082
- Characteristics: higher strength and extrusion performance than 6061, good weldability and corrosion resistance.
- Application: extruded profiles (such as keels, ribs), load-bearing structural parts of large ships.
- Typical state: T6, T651.
Please note that different types of marine grade aluminum alloy materials may be selected for different application scenarios, and the specific selection will be determined according to the required performance (such as strength, corrosion resistance, weldability, etc.).
Grade selection basis
- Corrosion resistance: 5000 series aluminum alloys (such as 5083, 5086) are the first choice for marine environments; 6000 series aluminum alloys need to be combined with anti-corrosion coatings.
- Strength requirements: High-strength grades (such as 5083 and 7075) are preferred for high-speed boats and warships; 5052 and 6061 can be used for small boats.
- Weldability: 5000 series aluminum alloys have excellent welding performance; 6000 series aluminum alloys need to control heat input.
- Processability: 6000 series aluminum alloys are easy to process and form; 5000 series aluminum alloys need to pay attention to work hardening.
The selection of aluminum grades for boat materials is usually based on factors such as strength, corrosion resistance and processing performance. 5000 series and 6000 series aluminum alloys are widely used in shipbuilding due to their good corrosion resistance and weldability. The specific alloy grade to be selected usually needs to be determined according to the design requirements and use environment of the ship.
