Closed-die precision forging
Shaped dies form the part in one or more stages. Precision designs use small drafts, thin webs and tight radii, reducing machining allowance.
Guide · High-performance forgings
Precision High-Performance Aluminium Forgings
Precision aluminium forgings are closed-die or ring-rolled parts forged close to final shape, with a grain flow that follows the part contour and a fully inspected, traceable structure. They are used where a casting is not sound enough and machining from plate wastes too much metal: aero-engine casings and rings, launch-vehicle frames, gas-turbine casings and nuclear heat-exchanger parts. This guide explains alloys, processes, inspection and how to specify them.
- Alloys
- 2014, 2219, 2618, 6061, 7050, 7075
- Forms
- Die forgings, rings, discs
- Standards
- ASTM B247 · EN 586 · AMS
- Inspection
- UT, PT, mechanical tests
What makes a forging "precision"?
Every forging improves the metal: hot working closes porosity, breaks up the cast structure and aligns the grain with the direction of metal flow. A precision forging goes further by forming the part much closer to its finished geometry, with smaller draft angles, thinner webs, tighter radii and smaller machining allowances than a conventional die forging.
The benefits are practical. Less metal is bought and machined away, which matters with costly high-strength alloys and long-lead aerospace material. The grain flow stays continuous around flanges, bosses and ribs instead of being cut through by machining, which improves fatigue and stress-corrosion resistance. And because every forging from the same die has the same shape and grain pattern, properties are more consistent from part to part than in parts hogged out of thick plate.
Precision forging is not one process but a combination: accurate dies, controlled billet and die temperatures (sometimes isothermal forging, where die and metal are at the same temperature), several forging stages, and careful heat treatment and stress relief. The term is used loosely in the market, so always define the tolerances, machining allowance and inspection you need, rather than relying on the label.
Aluminium alloys for high-performance forgings
| Alloy and temper | Character | Typical tensile / yield | Typical forged parts |
|---|---|---|---|
| 2014-T6 / T652 | High strength, good machinability; moderate corrosion resistance | 483 / 414 MPa (typical) | Aircraft fittings, wheels, engine mounts, heavy-duty brackets |
| 2219-T6 / T852 | Good strength from cryogenic to about 250 – 300 °C; weldable | See certificate | Launch-vehicle rings and frames, propellant tank parts, high-temperature housings |
| 2618-T61 | Retains strength at elevated temperature | See certificate | Compressor wheels, engine casings and pistons |
| 6061-T6 / T652 | Moderate strength, excellent corrosion resistance, weldable, anodises well | 310 / 276 MPa (typical) | Nuclear and heat-exchanger parts, marine and general engineering forgings |
| 7075-T73 / T7352 | Very high strength with improved stress-corrosion resistance over T6 | 505 / 435 MPa (typical) | Airframe fittings, landing-gear parts, rings and frames |
| 7050-T74 / T7452 | High strength and toughness in thick sections; good SCC resistance | See certificate | Thick airframe forgings, bulkheads, engine mounts |
Typical values are from ASM / Aluminum Association data and are not design minimums. Specified minimums depend on the forging type, thickness and test direction and are given in ASTM B247, EN 586-2 or the applicable AMS specification.
As a rule of thumb, 7xxx alloys in overaged tempers (T73, T74) are used for highest strength at room temperature, 2xxx alloys for strength at elevated temperature or where welding is needed (2219), and 6061 where corrosion resistance and weldability matter more than strength. The "52" suffix (T652, T7352, T7452) means the forging has been cold compressed after quenching to relieve residual stress, which keeps large or thin-walled parts stable during machining.
Typical precision-forged aluminium components
| Sector | Component | Usual alloys | Why forged |
|---|---|---|---|
| Aero engines | Fan cases and containment rings, intermediate casings, mounts | 2014, 2618, 7050, 7075 | Continuous grain flow around flanges; high fatigue and impact resistance |
| Space and launch vehicles | Y-section rings, frames, module shells, skirt sections, tank domes | 2219, 2014, 7050 | Weldable high-strength rings; strength from cryogenic to elevated temperature |
| Airframes | Bulkheads, fittings, landing-gear and wing attachment parts | 7075, 7050, 2014 | High strength-to-weight and damage tolerance |
| Gas turbines | Compressor casings, inlet guide-vane rings | 2618, 2014, 2219 | Elevated-temperature strength and dimensional stability |
| Nuclear power | Heat-exchanger tube sheets, support pads, instrument tube parts | 6061, 2219 | Low weight and corrosion resistance in secondary-loop service; clean, inspectable structure |
| Defence and high-end industrial | Missile bodies, housings, pump and compressor parts | 7075, 2014, 6061 | Soundness and property consistency under shock and fatigue |
Aluminium tube sheets are a good example of the trade-off. In a secondary-loop heat exchanger, a 6061 forged tube sheet can save a large share of the weight of a steel part and is easy to drill, while 2219 is chosen where higher strength at moderate service temperatures is needed. The alloy must be compatible with the tube material and the coolant chemistry, which is why such parts are always specified with the plant designer.
Forging routes for precision parts
Isothermal and hot-die forging
Dies heated to or near the metal temperature, so the metal does not chill against the die. Allows thinner sections and more complex shapes at lower pressing speed.
Ring rolling
A pierced preform is rolled between rolls to grow diameter and form rectangular or contoured cross-sections. Used for casings, flanges and launch-vehicle rings.
Contoured rings
Rings rolled to a profiled section (for example a Y or L shape) close to final geometry, cutting machining time and material.
Open-die (hand) forging
Blocks, discs and shafts forged between flat or simple dies; used for prototypes, small quantities and very large parts.
Heat treatment and stress relief
Solution treatment, quenching, cold compression or stretching (T652, T7352) and ageing, under controlled furnace uniformity.
Inspection and documentation
Typical inspection for high-performance forgings
- Chemical analysis
- Each heat or lot, to the alloy limits of the specification
- Mechanical tests
- Tensile tests on prolongations or sacrificial forgings, in the directions the specification calls for (L, LT, ST)
- Hardness and conductivity
- Checks of heat-treatment response; conductivity is used on 7xxx tempers to confirm overageing
- Ultrasonic testing
- Volumetric inspection to AMS-STD-2154 or ASTM E2375, class per drawing
- Surface inspection
- Penetrant testing for laps and cracks on finished or machined surfaces
- Macro-etch and grain flow
- Sectioned first-article forgings checked for grain-flow pattern and defects
- Documentation
- Mill test certificate (EN 10204 3.1), heat-treatment records and first-article report where required
Aerospace programmes often require additional approvals of the forging source and special processes. State these on the enquiry so they can be reviewed before quotation.
For flight-critical parts, the first article is usually sectioned to confirm the grain flow, and the forging process is then frozen: any change of die, press or heat-treatment route needs re-approval. Ask for this process control explicitly if your customer requires it.
How to specify a precision aluminium forging
- Drawing and modelProvide the finished-part drawing and 3D model. The forging drawing (with draft, allowances and test locations) is developed from it.
- Material specificationAlloy, temper and governing standard: ASTM B247, EN 586, or the relevant AMS or customer specification.
- Inspection levelUT class, penetrant, mechanical test directions and frequency, first-article requirements.
- Delivery conditionAs-forged, rough-machined or finish-machined; surface protection and packing.
- Quantity and schedulePrototype quantity, series volume and any call-off plan, so the die and process route can be chosen economically.
Metline supplies aluminium forgings and can arrange machining to drawing, with mill certificates and export packing for delivery worldwide on EXW, FOB, CIF or DAP terms.
References and standards
- ASTM B247 – Aluminum and Aluminum-Alloy Die Forgings, Hand Forgings, and Rolled Ring Forgings
- EN 586-2 – Aluminium and aluminium alloys: forgings, mechanical properties and additional property requirements
- AMS 2770 – Heat Treatment of Wrought Aluminum Alloy Parts
- AMS-STD-2154 – Inspection, Ultrasonic, Wrought Metals, Process for
- ASM Handbook, Volume 14A – Metalworking: Bulk Forming (forging of aluminium alloys)
Precision aluminium (aluminum) forgings: FAQ
What is the difference between a precision forging and a conventional die forging?
A precision forging is formed much closer to finished shape, with smaller draft angles, thinner sections and smaller machining allowances. It costs more in tooling but saves material and machining and keeps the grain flow intact in the finished part.
Which aluminium alloy is best for aerospace forgings?
It depends on the part. 7075-T73 and 7050-T74 give the highest strength with good stress-corrosion resistance; 2014 and 2618 are used at elevated temperatures; 2219 is chosen for weldable launch-vehicle structures.
Why are forgings preferred to parts machined from plate?
Forging aligns the grain with the part contour, improving fatigue and stress-corrosion performance, and wastes far less metal on complex shapes. Plate is often more economical for flat, simple parts or very small quantities.
What does the T652 or T7352 temper mean?
The forging was cold compressed by a small amount after quenching to relieve residual stresses, then aged. This keeps large or thin-walled forgings dimensionally stable during machining.
What inspection is normally applied?
Chemistry, tensile tests, hardness and conductivity, ultrasonic testing to AMS-STD-2154 or ASTM E2375, penetrant testing, and macro-etch of first articles, documented on an EN 10204 3.1 certificate.
Planning a precision forged part?
Send the drawing, alloy, specification and quantities. Our team will review the forging route and reply with a technical proposal and price.
