H131
Strain hardened by a controlled, heavy reduction for armour. Highest yield strength of the 5083 tempers and the standard choice for ballistic plate.
Weldable armour plate
5083, 5456 and 5059 Aluminium Armour Plate
5083, 5456 and 5059 are the weldable aluminium-magnesium armour alloys of MIL-DTL-46027, supplied as plate from 0.250 to 3.000 in thick. Strengthened by cold work to the hard H131 temper, they give dependable fragment protection, excellent corrosion resistance and easy welding, which is why most aluminium-hulled armoured vehicles are built from them. Metline supplies all three in standard and cut sizes, with mill and test certificates, worldwide.
- Specification
- MIL-DTL-46027
- Alloys
- 5083 · 5456 · 5059
- Tempers
- H131, H116, H321
- Thickness
- 0.250 – 3.000 in
Why 5xxx alloys dominate welded aluminium armour
5083 armour plate has protected light armoured vehicles since the 1960s. It is the baseline against which other aluminium armour is judged: not the strongest, but the easiest to weld into a large hull that stays sound for decades in wet, salty conditions.
The 5xxx alloys get their strength from magnesium held in solid solution and from cold work; they are not heat treated. That brings two big advantages for armour. First, welding does not wipe out a precipitation-hardened structure, so welded joints keep a high share of the parent strength and need no post-weld heat treatment. Second, there are no zinc- or copper-rich precipitates to drive stress-corrosion cracking, so the plate tolerates residual weld stresses and marine environments well.
MIL-DTL-46027 covers 5083, 5456 and 5059 wrought armour plate for welded and unwelded use, in nominal thicknesses from 0.250 to 3.000 in. The hard H131 temper is the main armour temper: a heavy, controlled amount of cold work raises yield strength well above the marine H116 temper, at some cost in formability. 5059, the newest of the three, contains more magnesium plus zinc and zirconium, and gives notably higher strength and ballistic resistance than 5083 at similar weldability.
Chemical composition (wt %)
MIL-DTL-46027 assigns each alloy a class. The limits below are the registered compositions; single values are maximums.
| Element | 5083 (Class 1) | 5456 (Class 2) | 5059 (Class 3) |
|---|---|---|---|
| Silicon (Si) | 0.40 | 0.25 | 0.45 |
| Iron (Fe) | 0.40 | 0.40 | 0.50 |
| Copper (Cu) | 0.10 | 0.10 | 0.25 |
| Manganese (Mn) | 0.40 – 1.0 | 0.50 – 1.0 | 0.6 – 1.2 |
| Magnesium (Mg) | 4.0 – 4.9 | 4.7 – 5.5 | 5.0 – 6.0 |
| Chromium (Cr) | 0.05 – 0.25 | 0.05 – 0.20 | 0.25 |
| Zinc (Zn) | 0.25 | 0.25 | 0.40 – 0.9 |
| Zirconium (Zr) | — | — | 0.05 – 0.25 |
| Titanium (Ti) | 0.15 | 0.20 | 0.20 |
| Others, each / total | 0.05 / 0.15 | 0.05 / 0.15 | 0.05 / 0.15 |
| Aluminium | Remainder | Remainder | Remainder |
Minimum mechanical properties by temper
Minimums for armour plate depend on alloy, temper and thickness band. The H131 values come from the armour specification; the H116 values are the ASTM B928 marine minimums, shown for comparison because some programmes use H116 or H321 plate for non-ballistic structure.
| Alloy and temper | Thickness (in) | Tensile, min (ksi) | Yield 0.2 %, min (ksi) | Elongation, min |
|---|---|---|---|---|
| 5083-H131 | 0.250 – 0.499 | 45 | 35 | 8 % |
| 5083-H131 | 0.500 – 2.000 | 45 | 37 | 8 % |
| 5083-H131 | 2.001 – 3.000 | 44 | 35 | 9 % |
| 5059-H131 | 0.250 – 0.499 | 57 | 44 | 8 % |
| 5059-H131 | 0.500 – 2.000 | 57 | 43 | 7 % |
| 5059-H131 | 2.001 – 3.000 | 50 | 42 | 8 % |
| 5083-H116 / H321 (ASTM B928) | up to 1.500 | 44 | 31 | 10 – 12 % |
| 5083-H116 / H321 (ASTM B928) | 1.501 – 3.000 | 41 | 29 | 12 % |
1 ksi = 6.895 MPa: 45 ksi ≈ 310 MPa, 57 ksi ≈ 393 MPa. Confirm values against the specification revision and the 5456 table on your order; the mill certificate reports actual results.
Physical properties (5083, typical)
- Density
- 2.66 g/cm³ (0.096 lb/in³)
- Modulus of elasticity
- 71 GPa
- Thermal conductivity
- About 117 – 121 W/m·K
- Melting range
- 574 – 638 °C
- Magnetic behaviour
- Non-magnetic
H131, H136, H116 and H321 explained
H136
A strain-hardened armour temper with lower strength and higher elongation than H131; used where more formability or toughness is wanted.
H116
Marine temper with controlled microstructure for resistance to exfoliation and intergranular corrosion, tested to ASTM G66 and G67. Used for non-ballistic hull and deck structure.
H321
Strain hardened and thermally stabilised; similar strength to H116 and also tested for corrosion resistance under ASTM B928.
Do not substitute H116 or H321 plate for H131 in ballistic areas: the lower yield strength gives noticeably lower V50 values. Conversely, H131 plate has less elongation, so tight bends are better made in H116 or designed out.
Standard sizes and plate weights
Supply range
- 5083-H131
- 0.250 – 3.000 in thick; common sheets 72 × 144 in
- 5083-H32 / H116
- 0.250 – 4.000 in thick; common sheets 48 × 144 in
- 5456-H116 and 5059-H131
- 0.125 – 1.500 in thick; cut to size
- Metric sizes
- Equivalent metric thicknesses and 1250 × 2500, 1500 × 3000, 2000 × 6000 mm plates on request
- Processing
- Saw cutting, waterjet profiling and bevelling for weld preparation
5083 weighs 2.66 kg per m² for every millimetre of thickness. Weights for a 72 × 144 in (1829 × 3658 mm) plate are shown below; use the plate weight calculator for other sizes.
| Thickness (in) | Thickness (mm) | kg per m² | 72 × 144 in plate (kg) |
|---|---|---|---|
| 0.250 | 6.35 | 16.9 | 113 |
| 0.375 | 9.53 | 25.3 | 170 |
| 0.500 | 12.7 | 33.8 | 226 |
| 0.750 | 19.05 | 50.7 | 339 |
| 1.000 | 25.4 | 67.6 | 452 |
| 1.250 | 31.75 | 84.5 | 565 |
| 1.500 | 38.1 | 101.3 | 678 |
| 2.000 | 50.8 | 135.1 | 904 |
| 2.500 | 63.5 | 168.9 | 1130 |
| 3.000 | 76.2 | 202.7 | 1356 |
Ballistic acceptance under MIL-DTL-46027
Each lot of armour plate is accepted on V50 ballistic limit tests carried out to MIL-STD-662, using a projectile and obliquity set by the nominal thickness. The specification tabulates a minimum V50 for every thickness step, rising steeply as the plate gets thicker.
| Approximate thickness range | Test projectile | Obliquity |
|---|---|---|
| About 0.45 – 0.72 in | .30 calibre AP M2 | 30° |
| About 0.72 – 1.00 in | .50 calibre fragment-simulating projectile | 0° |
| About 1.00 – 1.40 in | 20 mm fragment-simulating projectile, and .30 calibre AP M2 | 0° |
| Thicker plate | Heavier AP and fragment threats as tabulated | 0° |
Bands are indicative and differ slightly by alloy class. The governing limits are those in the specification revision on the order.
Vehicle-level protection is usually defined by NATO STANAG 4569 (AEP-55) levels, which set the threats a complete vehicle must stop. The plate specification ensures each lot of material performs consistently; the vehicle designer then chooses thickness, obliquity and any add-on armour to reach the required STANAG level.
Welding, cutting and forming armour plate
Welding
MIG welding with 5183 or 5556 filler is standard; 5356 is used for lower-strength joints. Welds in H131 plate lose part of the cold-work strength in the heat-affected zone, so weld locations are kept away from the most exposed areas where possible.
Cutting
Plasma, waterjet and saw cutting all work. Waterjet avoids heat-affected edges; plasma-cut edges are usually dressed before welding.
Forming
H131 plate has limited ductility: use generous bend radii and test bends on offcuts first. Avoid heating to aid forming, which softens the plate.
Temperature limits
Avoid long exposure between about 65 °C and 200 °C, which can sensitise high-magnesium alloys to intergranular corrosion.
Where 5xxx armour plate is used
- Armoured personnel carriers and infantry vehicles: welded hulls, roofs and side walls
- Turrets and weapon stations: welded structures protecting crew and fire-control equipment
- Floors and belly plates: where weldability and ductility help resist blast
- Naval craft: protected superstructure, bridge and magazine areas, where corrosion resistance is essential
- Shelters and protected containers: fragment-resistant walls for field command posts
- Base structure for appliqué armour: a welded 5083 hull carrying bolt-on high-strength panels
How to order armour plate
- SpecifyAlloy and class, temper, specification revision, thickness, plate size or cut list, and quantity.
- Define testingBallistic acceptance, ultrasonic inspection, corrosion tests for H116/H321 and witness inspection as required.
- QuoteWe confirm availability, certification and delivery terms (EXW, FOB, CIF or DAP).
- DocumentEN 10204 3.1 certificate with chemistry and mechanical results; ballistic test reports where ordered.
- ShipInterleaved plates in seaworthy wooden cases, shipped subject to applicable export controls.
References and standards
- MIL-DTL-46027K – Armor Plate, Aluminum Alloy, Weldable 5083, 5456 and 5059
- ASTM B928 – High Magnesium Aluminum-Alloy Sheet and Plate for Marine Service
- MIL-STD-662F – V50 Ballistic Test for Armor
- NATO STANAG 4569 / AEP-55 – Protection Levels for Occupants of Armoured Vehicles
- US Army Research Laboratory ARL-TR-4427 – Ballistic Performance Testing of Aluminum Alloy 5059-H131 and 5059-H136
5083, 5456 and 5059 armour plate: frequently asked questions
What is the difference between 5083-H131 and 5083-H116?
H131 is a heavily strain-hardened armour temper with a minimum yield of about 35 – 37 ksi, chosen for ballistic performance. H116 is a marine temper with lower strength (about 29 – 31 ksi yield) but guaranteed resistance to exfoliation and intergranular corrosion.
Is 5059 better than 5083 for armour?
5059 has higher magnesium plus zinc and zirconium, giving H131 minimum tensile strengths around 57 ksi against 45 ksi for 5083, and better ballistic resistance at similar weldability. It usually costs more and is less widely stocked.
Can 5083 armour plate be welded without heat treatment?
Yes. 5xxx alloys are not heat treatable, so welds are made with 5183 or 5556 filler and used as welded. The heat-affected zone of H131 plate softens somewhat, which is allowed for in the design.
Which specification covers 5083 armor aluminum plate?
MIL-DTL-46027 covers weldable 5083, 5456 and 5059 armour plate from 0.250 to 3.000 in. Non-ballistic marine plate is ordered to ASTM B928 or EN 485.
How much does a 5083 armour plate weigh?
5083 weighs 2.66 kg per m² per millimetre of thickness. A 1 in (25.4 mm) plate of 72 × 144 in weighs about 452 kg.
What sizes are standard for 5083-H131 armour plate?
Common sheets are 72 × 144 in for H131 and 48 × 144 in for H32 and H116, in thicknesses from 0.250 in up. Cut-to-size panels and metric sizes are available on request.
Need weldable armour plate?
Send alloy, temper, thickness, size and quantity. We will reply with availability, test scope and a delivered price.
