5083
Al-Mg alloy with about 4.5 % magnesium. Non-heat-treatable, highly weldable and very corrosion resistant. Gives good fragment protection and is the natural choice when the forging is welded into a 5083 hull.
Forged armour
Forged 5083, 5456 and 7039 Aluminium Armour
Forged aluminium armour is used where an armour part has a shape that plate cannot give, such as a hatch, a turret ring section or a thickened hull corner, but must still meet ballistic requirements. MIL-DTL-45225F covers aluminium alloy armour die forgings from 3/4 in thick; 5083 and 5456 give weldable, corrosion-resistant forgings, while 7039 gives higher strength and armour-piercing resistance. Metline supplies forged armour to drawing and specification worldwide.
- Specification
- MIL-DTL-45225F
- Alloys
- 5083 · 5456 · 7039
- Thickness
- 3/4 – 4 in
- Form
- Die forgings to drawing
Why forge armour instead of machining it from plate?
A forging is worked into shape under a press or hammer, so the metal grain follows the outline of the part. Compared with a shape machined from thick plate, a forging has more uniform properties in all directions, fewer weak planes and less waste.
Armoured vehicles contain many parts that are thick and shaped at the same time: hatch covers and rings, sponson and corner sections, mounts for weapons and suspension, and thick transitions between hull plates. Machining these from plate wastes most of the material and can expose the weak short-transverse direction of the plate on critical faces. A die forging is close to the final shape, needs less machining, and has properties defined by the forging specification rather than by plate tests.
MIL-DTL-45225F is the US detail specification for forged aluminium alloy armour. It covers die forgings from 3/4 in up to 3 in thick for Type I Class A forgings and up to 4 in for Type I Class B forgings, and it sets chemistry, mechanical property and ballistic acceptance requirements.
5083, 5456 and 7039 for forged armour
5456
Higher-magnesium relative of 5083 with slightly higher strength. Used in the same way, with 5556 or 5183 filler for welding.
7039
Al-Zn-Mg alloy that is solution treated and aged. Higher strength and better armour-piercing resistance than the 5xxx alloys, but more sensitive to stress corrosion, especially near welds.
As a working rule, 5xxx forgings are chosen when the part is welded into the hull and the main threat is fragments, while 7039 forgings are chosen for bolted or lightly welded parts where armour-piercing resistance matters more than weldability.
Chemical composition of 5083, 5456 and 7039 (wt %)
| Element | 5083 | 5456 | 7039 |
|---|---|---|---|
| Silicon (Si) | 0.40 | 0.25 | 0.30 |
| Iron (Fe) | 0.40 | 0.40 | 0.40 |
| Copper (Cu) | 0.10 | 0.10 | 0.10 |
| Manganese (Mn) | 0.40 – 1.0 | 0.50 – 1.0 | 0.10 – 0.40 |
| Magnesium (Mg) | 4.0 – 4.9 | 4.7 – 5.5 | 2.3 – 3.3 |
| Chromium (Cr) | 0.05 – 0.25 | 0.05 – 0.20 | 0.15 – 0.25 |
| Zinc (Zn) | 0.25 | 0.25 | 3.5 – 4.5 |
| Titanium (Ti) | 0.15 | 0.20 | 0.10 |
| Others, each / total | 0.05 / 0.15 | 0.05 / 0.15 | 0.05 / 0.15 |
| Aluminium | Remainder | Remainder | Remainder |
Registered Aluminum Association limits; single values are maximums.
Minimum mechanical properties of forged armour
Forging specifications set minimums that depend on the alloy class and on the direction in which the test piece is taken relative to the grain flow. The higher values apply in the main grain direction, the lower ones across it.
| Alloy group | Thickness | Tensile strength, min | Yield strength (0.2 %), min | Elongation, min |
|---|---|---|---|---|
| 5083 / 5456 | 0.75 – 3.0 in | 40 – 42 ksi (276 – 290 MPa) | 32 – 33 ksi (221 – 228 MPa) | 4 – 7 % |
| 7039 | 0.75 – 4.0 in | 54 – 57 ksi (372 – 393 MPa) | 45 – 48 ksi (310 – 331 MPa) | 4 – 8 % |
Ranges summarise the with-grain and across-grain minimums commonly quoted for these forgings. Confirm the exact figures for each direction against the specification revision on your order.
Physical properties (typical)
- Density, 5083 / 5456
- 2.66 g/cm³
- Density, 7039
- 2.74 g/cm³
- Modulus of elasticity
- About 70 GPa
- Magnetic behaviour
- Non-magnetic
How forged armour is ballistically tested
Forged armour is accepted on ballistic tests of representative test plates as well as on mechanical tests. The test projectile changes with thickness, so that each thickness band is tested against a realistic threat. The V50 ballistic limit, the velocity at which half the shots are expected to perforate, must meet the minimum the specification sets for the nominal thickness, and the required V50 rises steeply with thickness.
| Nominal thickness band | Typical test projectile | Threat represented |
|---|---|---|
| About 0.7 – 1.1 in | .50 calibre fragment-simulating projectile (FSP) | Shell and mine fragments |
| About 1.1 – 1.7 in | .30 calibre AP M2 and 20 mm FSP | Rifle AP rounds and large fragments |
| About 1.7 – 3.0 in | .50 calibre AP M2 | Heavy machine-gun AP rounds |
| Over 3.0 in (7039 only) | Larger-calibre AP projectile | Cannon-calibre threats |
Bands are indicative; 7039 changes projectile at slightly lower thicknesses than the 5xxx alloys because it is stronger. The governing values are the tables in the specification.
Ballistic tests follow MIL-STD-662 procedures for V50 determination. For production parts, the purchaser and supplier agree how test plates represent the forgings, for example by forging test blocks from the same lot with the same reduction.
Inspection of armour forgings
- Chemistry: analysis of each melt or lot, reported on the certificate
- Tensile tests: per ASTM B557 in the directions required by the specification
- Ultrasonic testing: to detect internal laminations, bursts or porosity, typically to AMS-STD-2154 or the class set by the drawing
- Dye-penetrant inspection: of machined and critical surfaces for laps and cracks
- Stress-corrosion testing: for 7039, where the specification or programme requires it
- Dimensional inspection: against the forging and machining drawings
Typical forged armour parts
- Hatches and hatch rings: crew and escape hatches that must match the protection of the surrounding hull
- Turret and weapon-station parts: ring sections, mantlets and mounts
- Hull corners and transitions: thick sections where plates of different thickness meet
- Suspension and running-gear mounts: load-bearing brackets that also form part of the hull
- Underbody parts: thick, shaped sections that help resist blast from below
- Protective panels for fixed sites: shaped ballistic parts for shelters and guard posts
A typical example is a crew hatch: the frame is forged in 5083 so that it can be welded into a 5083 hull, and the hatch lid may be forged in 7039 and bolted on, giving the lid better AP resistance without welding it.
How to order forged armour
- SpecifyForging drawing, alloy, forging type and class, specification revision, quantity and machining condition (as-forged or machined).
- Define testingState ballistic, ultrasonic, penetrant and stress-corrosion requirements and any witness inspection.
- QuoteWe confirm feasibility, test scope, certification and delivery terms (EXW, FOB, CIF or DAP).
- DocumentEach lot ships with an EN 10204 3.1 certificate and test reports.
- ShipParts are protected, packed in wooden cases and shipped subject to applicable export controls.
References and standards
- MIL-DTL-45225F – Aluminum Alloy Armor, Forged
- MIL-DTL-46027 – Armor Plate, Aluminum Alloy, Weldable 5083, 5456 and 5059
- MIL-DTL-46063H – Armor Plate, Aluminum Alloy, 7039
- MIL-STD-662F – V50 Ballistic Test for Armor
- ASTM B247 – Aluminum and Aluminum-Alloy Die Forgings, Hand Forgings, and Rolled Ring Forgings
Forged aluminium armour: frequently asked questions
Which specification covers forged aluminium armour?
MIL-DTL-45225F, Aluminum Alloy Armor, Forged. It covers die forgings from 3/4 in to 3 in thick for Type I Class A and up to 4 in for Type I Class B, with mechanical and ballistic requirements.
Is a forging better than plate for armour?
For shaped, thick parts, yes. The grain follows the shape, properties are more even and less material is machined away. For flat panels, rolled armour plate is simpler and cheaper.
Can 5083 forgings be welded to 5083 armour plate?
Yes. 5083 and 5456 forgings weld readily with 5183 or 5556 filler and do not need heat treatment after welding, which is why they are used for parts welded into 5xxx hulls.
Why is 7039 not always used, given its higher strength?
7039 is more susceptible to stress-corrosion cracking than 5083, particularly in the heat-affected zone of welds, and it is harder to weld. It is chosen where AP resistance matters more and the part can be bolted or carefully welded and protected.
What testing comes with forged armour aluminum parts?
Chemistry and tensile tests on every lot, ultrasonic and penetrant inspection as specified, and ballistic V50 tests on representative test plates when the order calls for MIL-DTL-45225F acceptance.
Need forged armour parts?
Send the drawing, alloy, quantity and specification. We will reply with feasibility, test scope and a delivered price.
