5000 Series – Aluminium + Magnesium

The 5000 Series aluminium alloys are non-heat-treatable aluminium–magnesium alloys in which magnesium (Mg) is the principal alloying element, typically ranging from 2.0% to 5.5%.

These alloys are renowned for their excellent corrosion resistance (especially in marine environments), good weldability, moderate to high strength, and outstanding formability.

5000 series alloys offer one of the best strength-to-corrosion-resistance ratios among aluminium families and are widely used in marine, shipbuilding, automotive, pressure vessels, cryogenic applications, and structural fabrications.

Typical Chemical Composition

Magnesium increases strength by solid-solution strengthening while maintaining corrosion resistance.

Mechanical & Physical Properties

(Typical values – depend on temper and cold work)

Physical Properties

Density: ~2.66 g/cm³
Melting Point: ~570 – 635°C
Thermal Conductivity: 120 – 160 W/m·K
Electrical Conductivity: Moderate
Coefficient of Thermal Expansion: ~23 × 10⁻⁶ /°C
Non-magnetic

Mechanical Properties

Tensile Strength: 170 – 450 MPa
Yield Strength: 65 – 300 MPa
Elongation: 10 – 30%
Brinell Hardness: 45 – 110 HB
Elastic Modulus: ~69 GPa
Impact Toughness: Excellent (even at cryogenic temperatures)

Strengthening & Metallurgical Behavior

Strengthening Mechanism
Solid-solution strengthening by Magnesium
Cold working (strain hardening) increases strength

Heat Treatment
❌ Not heat-treatable

Strength increased through:

Rolling
Stretching
Work hardening (H tempers)

Microstructure
Fine, uniform grains
Excellent resistance to cracking and fatigue
Retains toughness at very low temperatures (cryogenic stability)

Key Characteristics

1. Exceptional Corrosion Resistance
Outstanding resistance to:
Seawater
Marine atmosphere
Industrial pollution
Ideal for marine and offshore applications

2. Excellent Weldability
No post-weld heat treatment required
Maintains strength and corrosion resistance after welding

3. High Strength-to-Weight Ratio
Stronger than 1000 & 3000 series
Lightweight compared to steel

4. Excellent Low-Temperature Toughness
Retains ductility and impact strength at cryogenic temperatures
Used in LNG and low-temperature storage tanks

5. Good Formability
Easily bent, rolled, stamped, and deep-drawn

Refining & Processing Properties

Forming & Fabrication
Excellent for:
Rolling
Bending
Stamping
Deep drawing

Welding
MIG / TIG welding suitable
Filler alloys: 5356, 5183, 5556
No cracking tendency

Machinability
Moderate
Better in harder tempers
Requires sharp tooling

Surface Treatment
Excellent anodizing (decorative & protective)
Suitable for painting and powder coating

Available Forms of 5000 Series Aluminium

Sheets & Plates
Coils (Hot & Cold Rolled)
Extrusions (limited profiles)
Bars & Rods
Pipes & Tubes
Foils
Marine-grade Plates
Custom Fabricated Components

Applications of 5000 Series Aluminium

1. Marine & Offshore
Ship hulls
Decks
Boat structures
Offshore platforms

2. Automotive Industry
Body panels
Fuel tanks
Underbody shields

3. Pressure Vessels & Cryogenic Equipment
LNG tanks
Storage vessels
Heat exchangers

4. Construction & Architecture
Roofing
Cladding
Curtain walls
Structural panels

5. Transportation
Rail coaches
Truck bodies
Tankers

6. Industrial Applications
Chemical tanks
Pipelines
Walkways and platforms

Advantages of 5000 Series Aluminium

Superior corrosion resistance
Excellent weldability
High strength without heat treatment
Lightweight and durable
Performs well in marine & low-temperature environments
Long service life with low maintenance

Why Choose 5000 Series Aluminium?

The 5000 Series aluminium alloys are the best choice for applications requiring corrosion resistance, structural strength, and weldability, especially in marine, offshore, and harsh environmental conditions.

They provide reliable mechanical performance, outstanding durability, and cost-effective fabrication, making them a preferred material for heavy-duty yet lightweight structures.