Closed-die forgings
Near-net-shape parts pressed in matched dies: fittings, brackets, hubs, wheels and housings. Least machining and best grain flow.
Die forgings, hand forgings and rolled rings
6061 Aerospace Aluminium Forgings
6061 aerospace forgings are die forgings, open-die (hand) forgings and rolled rings in 6061, heat-treated to T6 or T652 and certified to specifications such as AMS 4127, AMS 4248 and ASTM B247. Forging aligns the grain with the part shape and closes internal porosity, giving better toughness and ductility in all directions than a part machined from plate or bar. Metline supplies 6061 forgings to drawing, worldwide.
- Alloy
- 6061 (Al-Mg-Si-Cu)
- Tempers
- F, O, T4, T6, T652
- Types
- Die, hand, rolled ring
- Specs
- AMS 4127 · AMS 4248 · ASTM B247
Why use 6061 forgings in aerospace?
A forging is shaped by pressing or hammering a hot billet, so the metal's grain flows along the contour of the part. For a fitting, hub or ring that carries load in several directions, this gives more consistent ductility and fatigue behaviour than the same shape cut from plate, where properties in the thickness direction are weakest.
6061 is one of the easiest aluminium alloys to forge. It flows well at forging temperature, takes intricate die shapes and, after heat treatment to T6, gives a strong, weldable and corrosion-resistant part. It is chosen for moderately loaded fittings, wheels and hubs, rings, housings and valve bodies where 2014, 7050 or 7075 forgings would be stronger than needed and harder to protect from corrosion.
Specifications for 6061 forgings
| Specification | Scope | Temper |
|---|---|---|
| SAE AMS 4127 | Die forgings (up to 4 in / 102 mm thick at heat treatment), hand forgings, forged and rolled rings, and forging stock | T6 |
| SAE AMS 4248 | Hand forgings and rolled rings, stress-relieved by compression | T652 |
| AMS-QQ-A-367 | General aluminium alloy forgings (former federal specification) | T6, T652 and others |
| ASTM B247 / B247M | Die, hand and rolled-ring forgings, commercial and industrial | O, T4, T6, T652 |
| EN 586-2 / -3 | European forgings: mechanical properties and tolerances (EN AW-6061) | T6 |
Forging specifications set maximum section thicknesses for each temper. For thick or heavy parts, check the limit before finalising the design.
6061 chemical composition (wt %)
Forgings use the standard 6061 composition. Copper is 0.15 – 0.40 % and chromium 0.04 – 0.35 %; tables that list copper as 0.15 % maximum or chromium as 0.04 % maximum are incorrect.
| Element | Minimum | Maximum | Role in the alloy |
|---|---|---|---|
| Silicon (Si) | 0.40 | 0.80 | Forms the strengthening Mg2Si phase with magnesium |
| Iron (Fe) | — | 0.70 | Impurity; held low for toughness and surface quality |
| Copper (Cu) | 0.15 | 0.40 | Adds strength; a small penalty in corrosion resistance |
| Manganese (Mn) | — | 0.15 | Grain structure control |
| Magnesium (Mg) | 0.80 | 1.20 | Main strengthening element with silicon |
| Chromium (Cr) | 0.04 | 0.35 | Limits recrystallisation, improves stress-corrosion resistance |
| Zinc (Zn) | — | 0.25 | Impurity |
| Titanium (Ti) | — | 0.15 | Grain refiner |
| Others, each / total | — | 0.05 / 0.15 | |
| Aluminium (Al) | Remainder | About 95.8 – 98.6 % |
Mechanical properties of 6061 forgings
Guaranteed properties for forgings are lower than for plate or bar in the same temper, because a forging is tested in several directions and thick sections cool more slowly when quenched. Values below are representative; the exact minimums depend on forging type, thickness and test direction in the governing specification.
| Condition | Tensile strength | Yield strength (0.2 %) | Elongation |
|---|---|---|---|
| T6 die forging, minimum (longitudinal, typical spec level) | About 260 MPa / 38 ksi | About 240 MPa / 35 ksi | About 7 % |
| T6 / T652, typical | 310 MPa / 45 ksi | 276 MPa / 40 ksi | 12 % |
| T4, typical | 240 MPa / 35 ksi | 145 MPa / 21 ksi | 22 % |
| O, typical | 125 MPa / 18 ksi | 55 MPa / 8 ksi | 25 % |
Typical Brinell hardness is about 95 HB in T6 and about 65 HB in T4. T451 is a plate and rolled-bar temper and is not normally used for forgings.
Physical properties of 6061 (T6)
- Density
- 2.70 g/cm³ (0.0975 lb/in³)
- Modulus of elasticity
- 68.9 GPa (10,000 ksi)
- Thermal conductivity
- 167 W/m·K
- Electrical conductivity
- About 43 % IACS
- Coefficient of thermal expansion
- 23.6 µm/m·°C (20 – 100 °C)
- Melting range
- 582 – 652 °C
6061 forging types and tempers
Open-die (hand) forgings
Blocks, discs, shafts and bars shaped between flat or simple tools. Used for prototypes, low quantities and large parts machined to shape.
Rolled rings
Seamless rings rolled from a pierced blank, for flanges, bearing housings, adaptor rings and launch-vehicle joints.
T6
Solution treated, quenched and artificially aged. The standard temper for 6061 forgings.
T652
T6 with 1 – 5 % cold compression after quenching to relieve stress. Chosen for large hand forgings and rings that will be heavily machined.
F / O / T4
As-forged, annealed or naturally aged conditions, for parts that will be further worked or heat-treated by the user.
Inspection and certification
Typical requirements
- Chemistry
- Analysis per cast of forging stock
- Mechanical tests
- Tensile tests from prolongations or sacrificial parts, in the directions the specification requires
- Hardness and conductivity
- Checks on every part or a sample to confirm heat treatment
- Ultrasonic inspection
- To AMS-STD-2154 or ASTM B594 at the ordered class
- Grain flow
- Macro-etch of a sectioned first article to confirm flow lines where required
- Certificate
- EN 10204 3.1 certificate with lot traceability; first-article inspection reports on request
Where 6061 forgings are used
- Airframe fittings and brackets in secondary structure and systems installations
- Wheels and hubs for light aircraft, UAVs and ground-support equipment
- Hydraulic and fuel-system housings, valve bodies and manifolds
- Rings and flanges for launch-vehicle tank joints, adaptors and satellite interfaces
- Rotor, gimbal and antenna mounts where weldability and machinability help assembly
For highly loaded primary structure such as wing-to-fuselage fittings or landing-gear parts, 7050-T7452 or 7075-T73 forgings are normally specified. 6061 suits parts where the design stress is moderate and corrosion resistance or weldability is important.
How to order 6061 forgings
- SpecifyAlloy and temper, a forging or machined-part drawing, test and ultrasonic requirements, quantity and the governing specification with its revision (for example AMS 4127, AMS 4248 or ASTM B247).
- ConfirmWe confirm the specification can be met, the tolerance class, any extra tests and the delivery terms (EXW, FOB, CIF or DAP).
- InspectMaterial is checked for dimensions, surface condition and identification; tests named on the order are carried out or arranged with a third party.
- DocumentEach lot ships with a mill test certificate to EN 10204 3.1 showing chemistry and mechanical results, traceable to the cast or lot number.
- Pack and shipExport packing in sealed, moisture-protected wooden cases or on pallets, shipped by sea or air to your port or door.
References and standards
- SAE AMS 4127 – Aluminum Alloy, Forgings and Rolled or Forged Rings, 6061-T6
- SAE AMS 4248 – Aluminum Alloy Hand Forgings and Rolled Rings, 6061-T652
- ASTM B247 – Standard Specification for Aluminum and Aluminum-Alloy Die Forgings, Hand Forgings, and Rolled Ring Forgings
- EN 586 – Aluminium and aluminium alloys: forgings
- The Aluminum Association – International Alloy Designations and Chemical Composition Limits (Teal Sheets)
6061 aluminium (aluminum) forgings: frequently asked questions
Which AMS specification covers 6061-T6 forgings?
AMS 4127 covers 6061-T6 die forgings, hand forgings and forged or rolled rings. AMS 4248 covers T652 hand forgings and rolled rings that are stress-relieved by compression.
Are 6061 forgings stronger than 6061 plate?
Typical strength is similar, but forgings give more uniform properties in all directions and better fatigue behaviour at features such as lugs and bosses, because the grain follows the part shape.
What is the T652 temper?
T6 with a controlled cold compression of about 1 – 5 % after quenching, which reduces residual stress so large forgings and rings distort less when machined.
Can 6061 forgings be welded?
Yes. 6061 forgings weld with 4043 or 5356 filler, which is one reason they are chosen over 2xxx and 7xxx forgings. The heat-affected zone loses some strength unless re-heat-treated.
Should I choose open-die or closed-die forging?
Closed-die forging suits larger quantities and gives near-net shape with the best grain flow. Open-die forging suits prototypes, small quantities and large parts that will be machined.
Do you supply 6061 forgings with ultrasonic test reports?
Yes. Forgings can be supplied with ultrasonic inspection to AMS-STD-2154 or ASTM B594 and an EN 10204 3.1 certificate, shipped worldwide.
Need 6061 forgings for an aerospace part?
Send your drawing, temper, quantity and specification. Our team will propose a forging route and a delivered price.
