5083-H131 Aluminum Plate Overview
5083-H131 aluminum is a non-heat-treatable, cold-worked aluminum-magnesium alloy designed for demanding marine and military applications. It belongs to the strain-hardened H1 series: the prefix H1 indicates that the alloy is strain-hardened without thermal treatment, and the suffix 31 denotes a specific level of stabilization tailored for marine and defense use. Compared with 5083-H32, the H131 temper undergoes additional cold working and stabilization to deliver consistent mechanical properties under dynamic load and impact.
Chemical Composition
The nominal composition of 5083-H131 includes magnesium at 4.0 to 4.9 percent, manganese at 0.4 to 1.0 percent, chromium at 0.05 to 0.25 percent, and silicon, iron, copper, zinc, and titanium each limited to 0.4 percent or less, with the balance aluminum. The high magnesium content provides excellent strength through strain hardening, while manganese and chromium refine the grain structure and enhance resistance to intergranular corrosion.
Mechanical Properties
Typical mechanical values for 5083-H131 plate are a tensile strength of 305 to 385 MPa, a yield strength at 0.2 percent offset of at least 215 MPa, elongation of 10 to 12 percent, and a density of 2.66 g/cm3. These properties make 5083-H131 one of the strongest alloys in the 5000 series, suitable for structural and ballistic applications. Because the alloy may be prone to stress corrosion cracking in some conditions, operating temperatures should generally remain below 65 degrees Celsius for optimal long-term performance.
Corrosion Resistance
With its high magnesium content and controlled impurities, 5083-H131 offers outstanding resistance to seawater and industrial corrosion. The stable oxide film self-repairs if scratched, preventing progressive attack, which is why the alloy is a standard choice for hull plating and offshore structures. For critical saltwater service, the alloy is also covered by marine-grade specifications that verify corrosion performance.
Fabrication and Welding
5083-H131 offers excellent weldability using GMAW and GTAW processes, with 5183 the recommended filler alloy; welded zones may experience reduced strength in the heat-affected area. Despite its high strength, the plate maintains good ductility and is suitable for bending, rolling, and deep drawing when proper techniques are used. Machining requires sharp tools and adequate cooling because of the strain-hardened condition, and no post-fabrication heat treatment is required because the mechanical properties are stable.
Applications and Standards
In marine and shipbuilding, 5083-H131 is used extensively for hull plating, decks, superstructures, and piping systems on ships and offshore platforms. In defense, it is approved under MIL-DTL-46027 and used in military vehicles and ballistic protection systems, meeting V50 ballistic test requirements at a lighter weight than traditional materials. It is also ideal for LNG and LPG storage tanks and other cryogenic systems, and for aircraft fuel tanks, tanker trucks, and pressure vessels. Applicable standards include ASTM B209M, ASME SB209, ASTM B928M for marine grade, MIL-DTL-46027 for defense, and classification society approvals from DNV, Lloyd's, and ABS for shipbuilding.
FAQ
Q: What does the H131 temper mean?
A: H1 means strain-hardened without thermal treatment, and 31 indicates a stabilized condition tailored for marine and defense applications with consistent impact performance.
Q: Is 5083-H131 weldable?
A: Yes. It welds well with GMAW and GTAW using 5183 filler, though the heat-affected zone may show somewhat reduced strength.
Q: Why is 5083-H131 used in defense applications?
A: It meets MIL-DTL-46027 and V50 ballistic test standards, providing strong protection at a lighter weight than traditional armor materials.
Q: What temperature limit applies to 5083-H131?
A: Operating temperatures should generally stay below 65 degrees Celsius because the alloy may be prone to stress corrosion cracking at higher temperatures.
Q: How does H131 compare with H116?
A: H131 offers higher strength and ballistic resistance, while H116 is preferred for ship hulls where maximum corrosion resistance and stability are the priority.
