Which Al 6000 Series Are Used in Shipbuilding
Al 6000 series aluminum alloys, with magnesium and silicon as their main alloying elements, achieve a perfect balance between strength, corrosion resistance, and machinability thanks to their heat-treatable strengthening properties, making them a staple in ship structures. Among them, 6061 and 6082 are two of the most commonly used 6000 aluminum alloy grades.
6082 Aluminum Alloy
As a higher-strength grade of 6-series aluminum alloys, 6082 aluminum alloy has superior mechanical properties compared to 6061, with a tensile strength exceeding 310 MPa, particularly excelling in bearing static heavy loads.
This characteristic makes it a "dedicated material" for load-bearing structures in ships, primarily used in profiles in core components with stringent strength requirements, forming a "strong-weak complementary" application pattern with 6061 aluminum alloy.
In the superdeck support structure, midship bulkhead frames, and ribs of large cargo ships, 6082 profiles are the absolute mainstay. These components need to withstand the combined effects of cargo weight, the ship's own weight, and seawater buoyancy over long periods. The high strength of 6082 ensures structural stability and prevents fatigue deformation during long-term service.
Furthermore, in the deck load-bearing beams of fishing boats and the keel reinforcements of yachts, 6082 profiles, with their advantages of "high strength + easy welding," have become the optimal solution to replace steel. 6082 aluminum plate is also used although it is not so popular as its profile.
6061 Aluminum Alloy
As a "star product" of the 6-series aluminum alloys, A6061 aluminum belongs to the Al-Mg-Si alloy system. After T6 and T651 tempering, its tensile strength can reach 290-320MPa, possessing both excellent weldability and seawater corrosion resistance. Its greatest advantage lies in its "combination of rigidity and flexibility," capable of being extruded into high-strength profiles and rolled into functional plates, adapting to the diverse needs of ships, from load-bearing structures to protective components.
Profile Forms
The application of 6061 aluminum alloy profiles in ships is concentrated in load-bearing structures. Common I-beams, channel profiles, T-beams, and tubular profiles constitute the "skeleton system" of the ship. In the hull frames of small yachts and patrol boats, 6061-T651 profiles, due to their stress-relieving tensile properties, offer excellent processing stability and can precisely match the complex curved surfaces of the bow and stern, bearing the dynamic loads from wind and waves.
In the mast manufacturing of catamarans, 6061 round tubular profiles are 60% lighter than traditional steel, lowering the ship's center of gravity and providing stronger resistance to wind vibrations, ensuring navigational stability. Furthermore, 6061 hollow profiles are frequently used in ship ventilation ducts, railing supports, and other components, ensuring structural strength while reducing weight.
Sheet Metal Forms
6061 aluminum alloy sheets are known for their functionality in shipbuilding, with tread plates being the most representative application. Rolled into diamond or five-bar textured patterns, their surface friction coefficient is increased to 0.6-0.8, far exceeding the 0.2-0.3 of ordinary aluminum sheets, effectively preventing slippage on wet decks.
After anodizing, these plates boast a corrosion resistance lifespan exceeding 20 years, making them standard equipment on the decks of passenger ships, ferries, and other vessels with high passenger density.
In areas such as gangways and passageways, 6061 flat plates are welded together to form protective panels, balancing corrosion resistance with ease of maintenance. Routine rinsing with fresh water is sufficient to remove salt stains, reducing maintenance costs.
Other 6-series aluminum alloys
Besides 6061 and 6082, grades such as 6063 and 6005A from the 6-series family also have a place in shipbuilding. Among them, 6063 aluminum alloy is renowned for its excellent corrosion resistance and decorative properties. With a copper content of less than 0.1%, its corrosion resistance in marine environments surpasses that of 6061, and it is commonly used in ship outfitting components such as porthole frames and door components.
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