COMPREHENSIVE TECHNICAL ANALYSIS AND DATASHEET OF ALUMINIUM 5083 FASTENERS
Aluminium 5083 (UNS A95083) stands as the absolute heavyweight champion of non-heat-treatable aluminium alloys. By heavily alloying the aluminium base with 4.0% to 4.9% Magnesium (Mg) and critical strengthening additions of Manganese and Chromium, this alloy achieves the highest structural strength available without requiring thermal baking. It is globally renowned for its exceptional performance in the harshest environments imaginable—from deep-sea marine applications to extreme cryogenic containment.
Beyond its raw tensile strength, Aluminium 5083 is famous for its near-total immunity to seawater and industrial chemical pitting. Unlike many structural metals that become dangerously brittle at sub-zero temperatures, 5083 retains exceptional fracture toughness down to absolute zero. This makes Aluminium 5083 fasteners the undisputed choice for LNG (Liquid Natural Gas) storage facilities, heavy naval shipbuilding, and commercial rail transport where high-stress structural integrity and extreme environmental resistance must coexist.
■ Product Overview & Specifications
| Material Classification | High-Strength Non-Heat Treatable Aluminium (Marine/Cryogenic Grade) |
|---|---|
| UNS Designation | A95083 |
| Microstructure | Alpha Solid Solution with Mn/Cr Dispersoids |
| Magnetic State | Completely Non-Magnetic |
| Density | 2.66 g/cm³ (0.096 lb/in³) |
| Size Range | Metric: M4 to M48 | Imperial: 3/16" to 2" |
| Primary Attribute | Highest Strength Non-Heat Treatable Alloy & Cryogenic Toughness |
■ Proprietary Datasheet Download (GATED)
Aluminium 5083 Marine/Cryo Grade — Complete Technical Datasheet
Contains detailed ultra-low temperature impact testing data (down to -195°C), optimal TIG/MIG welding filler recommendations for structural joints, and marine classification compliance parameters.
⬇ DOWNLOAD DATASHEET■ MTC Integration Section
In heavy structural and cryogenic engineering, alloy purity is a matter of life and safety. The heavy Magnesium and Manganese additions must be perfectly balanced to prevent stress-corrosion cracking over time. Ananka ensures every 5083 fastener order is backed by stringent, verified mill traceability.
- EN 10204 Type 3.1: Validates the critical 4.0–4.9% Magnesium loading, verifies Manganese/Chromium levels for grain refinement, and confirms the specific marine-grade strain-hardened temper (e.g., H116 or H321).
- EN 10204 Type 3.2: Routinely facilitated for LNG transport carriers, offshore drilling platform construction, and naval defense contracts requiring sign-offs from major maritime classification societies (ABS, DNV, Lloyd's).
■ Chemical Composition
The 5083 alloy takes the marine-resistance concept of 5052 and supercharges it for structural load-bearing. It features nearly double the Magnesium and introduces a significant amount of Manganese (Mn) to increase the metal's recrystallization temperature, vastly improving its strength after welding.
| Aluminium (Al) | Magnesium (Mg) | Manganese (Mn) | Chromium (Cr) | Iron (Fe) | Silicon (Si) |
|---|---|---|---|---|---|
| Balance (~92.4) | 4.00 – 4.90 | 0.40 – 1.00 | 0.05 – 0.25 | 0.40 Max | 0.40 Max |
■ Mechanical Properties
| Mechanical Property | Typical Limits (H116 / H321 Marine Temper) |
|---|---|
| Tensile Strength | 40,000 - 52,000 psi (275 - 350 MPa) |
| Yield Strength | 24,000 - 33,000 psi (165 - 228 MPa) |
| Elongation (in 2 inches) | 10% - 16% |
| Hardness (Brinell) | ~ 75 HB |
■ Equivalent Grades & Designations
| Standard / System | Designation |
|---|---|
| ASTM Specifications | ASTM B211 / ASTM B316 (Wire, Rod) |
| Common Trade Names | Structural Marine Aluminium, Alloy 5083 |
| European Equivalent | EN AW-5083 / AlMg4.5Mn0.7 (DIN 3.3547) |
| Military / Marine Std | MIL-DTL-46027, QQ-A-200/4 |
■ Applications & Industries
- Marine & Naval Construction: Structural hull bolts, heavy-duty marine brackets, and bulkhead fasteners on fast ferries, commercial shipping vessels, and naval frigates.
- Cryogenics & LNG Transport: Pressure vessel bolts and retaining hardware for liquid natural gas (-162°C) and liquid nitrogen storage tanks where standard steel would shatter like glass.
- Heavy Transport & Defense: Structural rivets and specialized bolting for military armored vehicles, mine cars, and commercial dump truck bodies requiring exceptional impact resistance.
■ Compatible Fastener Assemblies
| Mating Bolts/Machine Screws | Internal Threads (Nuts) | Washers |
|---|---|---|
| 5083 Hex Bolts & Structural Rivets | 5083 or 6061 Heavy Hex Nuts | 5083 Flat & Belleville Washers |
■ Torque & Installation Guidelines
Aluminium 5083 is a highly rigid, strong material compared to lower-series aluminiums, allowing for robust clamping forces in structural applications. However, high-magnesium alloys are highly susceptible to thread galling (cold welding) under load. Generous application of dialectric or molybdenum-disulfide anti-seize is mandatory during heavy torqueing.
| Nominal Diameter | Threads Per Inch (UNC) | Max Target Torque (in-lbs) | Max Target Torque (ft-lbs) |
|---|---|---|---|
| 1/4" | 20 | 55 - 65 | ~ 5.0 |
| 3/8" | 16 | 170 - 190 | ~ 15.0 |
| 1/2" | 13 | 350 - 380 | ~ 30.0 |
| 3/4" | 10 | 1100 - 1250 | ~ 100.0 |
■ Frequently Asked Questions
1. What makes 5083 so different from 5052 if they are both "Marine Grade"?
Think of 5052 as the "sheet metal" marine grade, and 5083 as the "structural plate" marine grade. Aluminium 5083 contains nearly twice the Magnesium and adds Manganese. This makes 5083 significantly stronger and more rigid, ideal for heavy load-bearing structural hulls and pressure vessels. 5052 is softer, making it better for intricate bending, forming, and lightweight panelling.
2. Why is Aluminium 5083 used in cryogenic (ultra-cold) environments?
Many metals, notably standard carbon steel, undergo a "ductile-to-brittle transition" when exposed to extreme cold. If struck, they will shatter like glass. Aluminium 5083 has a Face-Centered Cubic (FCC) crystalline structure that does not suffer from this transition. In fact, as the temperature drops toward absolute zero, 5083 actually increases in tensile strength and yield strength while maintaining its excellent fracture toughness.
3. Can 5083 fasteners be used in high-temperature environments?
No, and this is a critical limitation. Alloys with high Magnesium content (over 3.5%), like 5083, become highly susceptible to stress-corrosion cracking (SCC) if exposed to continuous operating temperatures above 65°C (150°F). For high-temperature environments, lower-magnesium alloys or different material families must be specified.