7A52-T6
Weldable Al-Zn-Mg alloy that matches 7A52 armour plate, so a forged node can be welded straight into the hull. Medium-high strength with good toughness.
Armour forgings
7A52, 7050 and 2A50 Aluminium Forgings for Armour
Forgings in 7A52, 7050 and 2A50 supply the thick, shaped parts of armoured vehicles: hatch rings, mounts, brackets and load-bearing nodes. 7A52-T6 is weldable to 7A52 armour plate, 7050-T74 gives the highest strength with good stress-corrosion resistance, and 2A50-T6 is a forgeable medium-strength alloy for complex shapes. Metline supplies all three to drawing, inspected and certified, worldwide.
- Alloys
- 7A52 · 7050 · 2A50
- Tempers
- T6 · T74
- Forms
- Die, hand, rolled ring
- Tests
- Tensile, HB, fracture, UT
Choosing an alloy for armour forgings
A forging is chosen when a part is thick, shaped and highly loaded, and when the designer wants the grain to follow the shape. In armoured vehicles that means parts such as hatch rings, turret ring sections, suspension mounts and towing eyes.
7050-T74
High-strength Al-Zn-Mg-Cu aerospace alloy. The over-aged T74 temper gives much better stress-corrosion resistance than T6, with strength well above 7A52. Bolted rather than welded.
2A50-T6
Al-Mg-Si-Cu forging alloy with good hot workability, used for complex medium-strength parts. Bolted rather than welded.
Chemical composition (wt %)
| Element | 2A50 | 7A52 | 7050 |
|---|---|---|---|
| Silicon (Si) | 0.7 – 1.2 | 0.25 | 0.12 |
| Iron (Fe) | 0.70 | 0.30 | 0.15 |
| Copper (Cu) | 1.8 – 2.6 | 0.05 – 0.20 | 2.0 – 2.6 |
| Manganese (Mn) | 0.40 – 0.80 | 0.20 – 0.50 | 0.10 |
| Magnesium (Mg) | 0.40 – 0.80 | 2.0 – 2.8 | 1.9 – 2.6 |
| Chromium (Cr) | — | 0.15 – 0.25 | 0.04 |
| Zinc (Zn) | 0.30 | 4.0 – 4.8 | 5.7 – 6.7 |
| Titanium (Ti) | 0.15 | 0.05 – 0.18 | 0.06 |
| Zirconium (Zr) | — | 0.05 – 0.15 | 0.08 – 0.15 |
| Nickel (Ni) | 0.10 | — | — |
| Aluminium | Remainder | Remainder | Remainder |
Single values are maximums. 7050 limits follow the Aluminum Association registration; 2A50 and 7A52 follow GB/T 3190.
Minimum mechanical properties by test direction
Forging properties are specified in three directions: longitudinal (along the main grain flow, or tangential in a rolled ring), transverse (or axial) and short transverse (or radial). Strength and especially elongation are lowest in the short-transverse direction.
| Alloy / temper | Forging type | Direction | Tensile, min (MPa) | Yield, min (MPa) | Elongation, min | Hardness, min |
|---|---|---|---|---|---|---|
| 2A50-T6 | Die forging | Longitudinal | 385 | 275 | 10 % | 100 HBW |
| 2A50-T6 | Die forging | Transverse | 365 | 245 | 7 % | 100 HBW |
| 2A50-T6 | Die forging | Short transverse | 345 | — | 5 % | 100 HBW |
| 7A52-T6 | Die, hand or rolled ring | Longitudinal | 410 | 345 | 6 % | 120 HBW |
| 7A52-T6 | Die, hand or rolled ring | Transverse | 380 | — | 4 % | 120 HBW |
| 7A52-T6 | Die, hand or rolled ring | Short transverse | 360 | — | 2 %* | 120 HBW |
| 7050-T74 | Hand forging or rolled ring | Longitudinal | 475 | 406 | 9 % | 140 HBW |
| 7050-T74 | Hand forging or rolled ring | Transverse / short transverse | 468 | 399 | 3 – 4 % | 140 HBW |
*3 % minimum for forgings under 30 kg. Minimums fall with section thickness; the values that apply to your part are set by the forging specification and drawing. Hand-forged 2A50 has slightly lower minimums than die-forged.
Fracture inspection and oxide-film limits
Inclusions and oxide films left from the melt are planes of weakness in a forging. Armour forgings are therefore broken open on sample pieces and the fracture surface examined. It must be free of non-metallic inclusions, and the oxide film found within a set inspection area is limited by forging category.
| Forging category | Inspection area | Total oxide-film area, max | Single-spot area, max |
|---|---|---|---|
| I (most critical) | 0.01 m² | 4 mm² | 2 mm² |
| II | 0.01 m² | 6 mm² | 3 mm² |
| III | 0.01 m² | 8 mm² | 3 mm² |
- Chemistry of each melt, reported on the certificate
- Tensile and hardness tests in the directions required by the drawing
- Ultrasonic testing to the class set by the drawing (for example AMS-STD-2154 for 7050)
- Macro-etch and grain-flow checks on first-article forgings
- Dimensional inspection against forging and machining drawings
Typical armour forging applications
- Hatch rings and doors: forged 7A52 welded into a 7A52 hull
- Turret and weapon mounts: high-load 7050-T74 rings and brackets, bolted in place
- Suspension and running gear: arms, brackets and hull nodes
- Towing and lifting points: eyes and lugs that carry shock loads
- Fixed protection: shaped parts for protected shelters and installations
What to check when selecting armour forgings
- Joining methodIf the part is welded to 7A52 plate, use 7A52. If it is bolted and highly loaded, consider 7050-T74.
- Load and directionIdentify the short-transverse direction of the part and check the minimum properties there.
- CorrosionFor 7xxx forgings in wet or salty service, prefer over-aged tempers and specify coatings.
- InspectionAgree forging category, ultrasonic class and first-article tests before production.
- DocumentationAsk for an EN 10204 3.1 certificate with chemistry, mechanical and inspection results.
References and standards
- GB/T 3190 – Wrought aluminium and aluminium alloys: chemical composition
- AMS 4108 – Aluminum Alloy Die Forgings, 7050-T74
- ASTM B247 – Aluminum and Aluminum-Alloy Die Forgings, Hand Forgings, and Rolled Ring Forgings
- AMS-STD-2154 – Inspection, Ultrasonic, Wrought Metals
- The Aluminum Association – International Alloy Designations and Chemical Composition Limits
Armour forgings: frequently asked questions
Which forging alloy can be welded to armour plate?
7A52-T6 forgings are weldable to 7A52 armour plate. 7050 and 2A50 are not normally fusion welded in armour structures and are bolted.
Why is 7050 supplied in T74 rather than T6?
T74 is an over-aged temper that gives up some peak strength for much better resistance to stress-corrosion cracking and exfoliation, which matters in thick forgings.
What is the equivalent of 2A50?
2A50 has no exact AA equivalent. It is an Al-Mg-Si-Cu forging alloy; 2014 (stronger) and 6061 (weaker, more corrosion resistant) are the nearest common alternatives.
Why are oxide films checked on fracture surfaces?
Oxide films act as internal cracks under impact. Breaking sample forgings and limiting the oxide area found ensures the metal is clean enough for armour service.
Do you supply machined aluminum forgings?
Yes. Forgings can be supplied as forged, rough machined or finish machined to drawing.
Need forgings for an armour programme?
Send the drawing, alloy and quantity. We will reply with feasibility, inspection scope and a delivered price.
