What is 5086 grade aluminum?

Last Updated : Apr. 27, 2025

5086 aluminum is a high-strength marine-grade alloy, primarily composed of aluminum and magnesium. It belongs to the 5000 series of aluminum alloys, known for its excellent corrosion resistance, especially in seawater environments. Unlike some other alloys, 5086 is not heat treatable; instead, it achieves strength through cold working processes.

5086 aluminum plate is an industrial aluminum alloy plate material based on an aluminum-magnesium alloy core, belonging to the medium to high strength, high corrosion resistance, and good weldability category.

5086 Aluminum Composition

The typical chemical composition of 5086 aluminum alloy includes:

Magnesium (Mg): 3.5%–4.5%
Manganese (Mn): 0.2%–0.7%
Chromium (Cr): 0.05%–0.25%
Iron (Fe): ≤0.5%
Silicon (Si): ≤0.4%
Copper (Cu): ≤0.1%
Zinc (Zn): ≤0.25%
Titanium (Ti): ≤0.15%
Aluminum (Al): Remainder

5086 Aluminum Mechanical Properties

The mechanical properties of 5086 aluminum alloy vary depending on the temper:

O (Annealed)

Yield Strength: Approx. 120 MPa
Ultimate Tensile Strength: Approx. 260 MPa
Elongation: Up to 46%

H116 (Strain-Hardened)

Yield Strength: Approx. 207 MPa
Ultimate Tensile Strength: Approx. 290 MPa
Elongation: Approx. 12%

These values reflect a balance between strength and ductility, making the alloy suitable for various structural applications.

5086 Aluminum Physical Properties

Density: ~2.7 g/cm³
Melting Range: 570–640°C
Conductivity: Medium thermal/electrical conductivity (lower than pure aluminum)

5086 aluminum is a marine-grade alloy praised for its balanced strength, weldability, and outstanding corrosion resistance, making it the alloy of choice for harsh environments like seawater exposure and chemical handling. Its applications include shipbuilding, transportation, and industrial infrastructure, though it is less suitable for high-stress or high-temperature environments compared to other alloys.

5086 Aluminum Characteristics

Corrosion Resistance: Maintains excellent corrosion resistance when used long-term in seawater and humid environments, performing well in saltwater environments due to its magnesium content.
Strength: Medium to high strength (stronger than 5052 but slightly weaker than 5083). Tensile strength and yield strength vary with temper.
Weldability and Formability: Good; compatible with TIG, MIG, and resistance welding. Use of 5xxx filler alloys (e.g., 5356) to maintain performance.
Not Heat Treatable: Strengthened through cold working (strain hardening). Common tempers include H116 (marine-grade stability) and H32.
Medium Strength: Falls between low-strength pure aluminum and high-strength aerospace alloys, meeting industrial load-bearing requirements.

5086 Aluminum Standards and Tempers

ASTM: B209 (Sheet/Plate), B548 (Pressure Vessels).
EN: EN 573-3 (Designated as EN AW-5086).
Tempers: H116 (Optimized for corrosion resistance), H32, H34 (Cold worked tempers).

5086 Aluminum Corrosion Resistance

5086 aluminum alloy has excellent corrosion resistance, especially in marine environments. Its high magnesium content enhances its resistance to seawater corrosion, making it an ideal choice for shipbuilding and offshore structural applications.

5086 Aluminum Fabrication and Welding

Although 5086 aluminum alloy is not heat treatable, its strength can be increased through cold working. It is easy to weld using techniques such as MIG, TIG, and arc welding. However, care must be taken during welding to prevent softening in the heat-affected zone. The alloy's good formability and machinability further promote its use in various applications.

5086 Aluminum Applications

Due to its excellent strength, corrosion resistance, and weldability, 5086 aluminum is widely used in:

Marine Industry: Hull structures, decks, and superstructures of ships and yachts.
Transportation: Truck/trailer bodies, rail vehicles, fuel tanks, rail cars, tankers, and trailers.
Military: Armor plates and military vehicles.
Pressure Vessels: Storage tanks and cryogenic vessels.
Infrastructure: TV towers and drilling platforms.
Construction: Structural components in corrosive environments.

5086 Aluminum Advantages

High Strength: Maintains structural integrity in demanding applications.
Excellent Corrosion Resistance: Performs well in marine and acidic environments.
Good Weldability: Suitable for various welding techniques.
Non-Magnetic: Beneficial for certain specialized applications.
Better Corrosion Resistance Compared to Many Other Alloys.
Retains Good Ductility and Toughness at Low Temperatures.
Combines Good Formability and Strength, Making it an Ideal Choice for Welded Structures.

5086 Aluminum Limitations

Lower strength compared to heat-treatable alloys (such as 6xxx or 7xxx).
Not suitable for high-temperature applications (strength decreases above 150°C).
If not manufactured properly, high-magnesium alloys are at risk of stress corrosion cracking.

5086 Aluminum Considerations

Despite its many advantages, 5086 aluminum is prone to stress corrosion cracking under certain conditions, especially in high-stress environments. Therefore, careful design and material selection are critical to reducing this risk.

Tags: Marine Aluminum 5086