Key Properties Overview of 5083 H116 Aluminum
5083 H116 aluminum is a marine-grade alloy used in shipbuilding, offshore structures, pressure vessels, and transport equipment. Its typical tensile strength is about 305 MPa, yield strength about 215 MPa, and density 2.66 g/cm3. The material offers excellent corrosion resistance in saltwater and excellent weldability without post-weld heat treatment, which is why it is a foundation material for modern commercial aluminum shipbuilding.
Mechanical Properties
The H116 designation means the metal has been strain hardened to achieve specific structural targets without compromising its marine corrosion resistance. Typical mechanical properties include a tensile strength of about 305 MPa, a yield strength of about 215 MPa, and elongation of 10% or higher. Tensile strength indicates the maximum stress the aluminum can withstand while being stretched before breaking, which matters in ship hulls absorbing wave impacts and dynamic sea loads. Yield strength is the point at which the material begins to deform permanently; a minimum of about 215 MPa ensures the structure returns to its original shape under standard operational loads. Elongation of 10% or more allows the metal to bend and form adequately during shipyard fabrication without cracking.
Physical Properties
Physical properties dictate how the material behaves regarding weight, heat transfer, and structural stiffness. Density is approximately 2.66 g/cm3, roughly one-third the weight of carbon steel, which is why the alloy is used to reduce vessel weight, fuel consumption, and draft. Thermal conductivity is about 120 W/m-C, and the elastic modulus is approximately 70 GPa, used by engineers to calculate deflection of beams and deck plates under load. The melting range is approximately 574-638 C. High thermal conductivity means heat dissipates quickly during welding, requiring specific power settings on TIG or MIG equipment to ensure full weld penetration.
Chemical Composition
The chemical makeup is regulated by international standards such as EN AW-5083 and ASTM B928. Magnesium content is 4.0-4.9%, manganese 0.4-1.0%, chromium 0.05-0.25%, silicon up to 0.40%, iron up to 0.40%, copper up to 0.10%, zinc up to 0.25%, titanium up to 0.15%, with the balance aluminum. Magnesium is the primary alloying element, providing high strength and outstanding resistance to alkaline and saltwater environments. Manganese and chromium refine the grain structure, increasing tensile strength and improving performance under weld thermal cycles. Copper, zinc, and iron are strictly limited because excessive impurities can create galvanic cells that accelerate corrosion.
Corrosion Resistance and Marine Performance
The high magnesium content of 5083 enhances resistance to seawater corrosion, while the H116 temper specifically improves resistance to exfoliation corrosion in marine environments. The H116 metallurgical process controls how magnesium precipitates within the aluminum grain boundaries; if uncontrolled, a continuous network can form and cause the metal to peel or flake apart. The H116 temper locks the grain structure in a safe configuration and is designed to pass corrosion testing such as ASTM G66, allowing the material to remain submerged in seawater for long periods without heavy protective coatings.
5083 H116 vs Other Aluminum Alloys
Compared with 5052, the 5083 alloy offers higher tensile and yield strength required for commercial ship hulls, while 5052 is easier to bend and form and is better suited to smaller, non-structural boat parts or general sheet metal work. Compared with 6061, the 5083 alloy provides superior corrosion resistance in raw seawater and retains excellent post-weld strength, whereas 6061 can lose a significant share of its strength in the heat-affected zone after welding. These differences make 5083 H116 the preferred choice for welded marine structures where both strength and corrosion resistance are mandatory.
FAQ
Q: Is 5083 H116 a marine grade aluminum?
A: Yes. It is specifically designed for marine environments due to its corrosion resistance. The H116 temper designation indicates that the metal has passed exfoliation and intergranular corrosion tests required by marine classification societies.
Q: Can 5083 H116 aluminum plate be welded?
A: Yes. It has excellent weldability and is widely used in welded structures, and it does not require post-weld heat treatment. Marine fabricators typically use 5183 or 5356 aluminum filler wire to achieve strong, corrosion-resistant weld seams.
Q: What is the density of 5083 H116 aluminum?
A: The density is approximately 2.66 g/cm3, significantly lighter than carbon steel at about 7.85 g/cm3, allowing lighter structures and higher fuel efficiency in vessels.
Q: Why does the H116 temper resist exfoliation corrosion?
A: The H116 temper controls how magnesium precipitates within the aluminum grain boundaries, avoiding the continuous network that causes peeling or flaking, and is designed to pass exfoliation corrosion testing for marine service.
Q: What standards cover 5083 H116 plate?
A: Common references include EN AW-5083 in Europe and ASTM B928 in North America, along with classification society rules for shipbuilding; the applicable standard and mill certificate should be confirmed with the supplier for each project.
Q: What filler wire is recommended for welding 5083?
A: Marine fabricators commonly use 5183 or 5356 filler wire, which provides strong and corrosion-resistant weld seams compatible with the 5083 base alloy.
