Machining allowance
Rolled rings are supplied oversize on OD, ID and height. Allow for scale-free clean-up, eccentricity and ovality; your supplier will confirm the allowance for the size.
Forged and machined rings
Aluminium Rings
Aluminium rings are annular parts defined by outside diameter, inside diameter and height, made either as seamless rolled-ring forgings, as rings cut from plate or tube, or as bent and welded rings. The route matters as much as the alloy: a rolled ring has grain flow around its circumference and the best fatigue strength, while a cut ring is cheaper for small quantities. Metline supplies aluminium rings in 6061, 7075, 2014, 2219, 5083 and other grades, rough or machined, to customers worldwide.
- Routes
- Rolled, forged, cut, welded
- Common grades
- 6061-T6, 7075-T6/T73, 2219
- Size basis
- OD × ID × height
- Standards
- ASTM B247 · EN 586 · AMS
What counts as an aluminium ring?
Any part shaped like a washer, flange blank or short thick tube is a ring in purchasing terms. What separates a good buy from a poor one is how the ring is made, because two rings with the same outside diameter, bore and height can have very different grain structure, strength in service and cost.
The highest-integrity route is the seamless rolled ring. A forged and pierced preform is rolled between a driven main roll and a mandrel roll while axial rolls control the height, so the wall thins and the diameter grows. The metal flows around the ring, giving a continuous circumferential grain that resists hoop stress and fatigue. Rolled rings are standard for aerospace and launch-vehicle structures, bearing housings, large flanges and gear blanks.
For prototypes, small quantities and lightly loaded parts, rings are cut from plate by waterjet, saw or plasma, machined from extruded or drawn tube, or bored from forged discs. Very large thin rings can be bent from extruded or rolled bar and joined by flash butt welding or friction stir welding. Each route has a place; the drawing and the load case decide which.
Rolled, forged, cut and welded rings compared
| Route | Grain structure | Strength and fatigue | Material yield | Best for |
|---|---|---|---|---|
| Seamless rolled ring | Circumferential, continuous | Highest hoop strength and fatigue life | High; near-net shape | Aerospace, bearings, flanges, pressure-bearing rings |
| Hand-forged (saddle) ring | Mostly circumferential | High | Moderate | Thick rings and small batches below rolling-mill economy |
| Cut from plate | Flat rolling grain, crosses the ring | Plate properties; lower in short-transverse | Low; centre is scrap | Prototypes, thin rings, low quantity |
| Machined from tube or bar | Axial (extrusion direction) | Good axially, lower tangentially | Good for small diameters | Small rings, bushes, spacers |
| Bent and welded | Along the bar, with a weld zone | Weld is the weak point unless tested | High | Very large, thin rings and frames |
Cutting a ring from plate wastes the centre, which can be 60 – 80 % of the plate area for a thin ring, and the ring wall crosses the plate's grain in every direction. For any ring larger than about half a metre in diameter, or loaded in fatigue, a rolled ring is usually cheaper in finished-part terms and clearly better in performance.
Ring alloys and typical properties
Ring alloys are the heat-treatable forging alloys plus 5083 for cryogenic and marine use. Values below are typical room-temperature properties of the alloy and temper from handbook data. Specified minimums for rolled rings depend on direction (tangential, axial, radial) and section thickness, and are set by ASTM B247, EN 586-2 or the applicable AMS specification.
| Alloy / temper | Tensile strength (typical) | Yield strength (typical) | Key traits | Typical ring use |
|---|---|---|---|---|
| 6061-T6 | 310 MPa | 276 MPa | Good corrosion resistance, weldable, economical | Flanges, vacuum chamber rings, general machinery |
| 6082-T6 | Similar to 6061-T6 | Similar to 6061-T6 | European structural forging alloy | Flanges, machinery and offshore rings |
| 7075-T6 | 572 MPa | 503 MPa | Very high strength; lower stress-corrosion resistance | Aerospace frames, high-load bearing housings |
| 7075-T73 | 505 MPa | 435 MPa | Overaged for stress-corrosion resistance | Aerospace rings in thick sections |
| 2014-T6 | 483 MPa | 414 MPa | High strength, good machinability | Aircraft and missile rings, wheels, heavy-duty parts |
| 2219-T6 | 414 MPa | 290 MPa | Weldable, tough at cryogenic and elevated temperature | Launch-vehicle tank and adapter rings |
| 2618-T61 | 440 MPa | 370 MPa | Retains strength up to about 200 °C | Engine and compressor rings |
| 5083-O / H111 | 290 MPa | 145 MPa | Non-heat-treatable, excellent at cryogenic temperature | LNG and marine rings |
Thick rolled rings are often supplied in T652 or T7352 tempers, where a controlled cold compression or expansion after quenching relieves residual stress and reduces distortion during machining. Ask for these tempers when a ring will be heavily machined.
Ring forging standards and inspection
| Standard | Scope |
|---|---|
| ASTM B247 / B247M | Aluminium alloy die forgings, hand forgings and rolled-ring forgings |
| SAE AMS 4127 | 6061-T6 forgings and rolled or forged rings for aerospace |
| Other SAE AMS specifications | Alloy- and temper-specific forgings and rings, e.g. 7075, 2014 and 2219 |
| EN 586-1 / -2 / -3 | Forgings: technical delivery conditions, mechanical properties, tolerances |
| ASTM B594 / SAE AMS 2630 | Ultrasonic inspection of aluminium wrought products |
| EN 10204 3.1 | Inspection certificate format |
A rolled ring order should state the test direction and location. Tangential specimens are the norm because that is the main load direction; axial and radial tests may be added for thick rings. Ultrasonic inspection to a stated class, macro-etch for grain flow and conductivity checks for 7xxx tempers are common additions for aerospace rings.
Ring sizes and weight calculation
Ring mass = π/4 × (OD² − ID²) × height × density. With dimensions in mm and a density of 2.70 g/cm³, multiply the volume in mm³ by 2.70 × 10⁻⁶ for kg. Use 2.80 g/cm³ for 7075 and 2.84 for 2219. Order weight for a rolled ring includes machining allowance on every face, so the forged ring will be heavier than the finished part.
| OD × ID × H (mm) | Annular area (mm²) | Weight (kg, 2.70 g/cm³) |
|---|---|---|
| 200 × 120 × 40 | 20,106 | 2.2 |
| 300 × 200 × 50 | 39,270 | 5.3 |
| 400 × 300 × 60 | 54,978 | 8.9 |
| 500 × 400 × 50 | 70,686 | 9.5 |
| 600 × 500 × 80 | 86,394 | 18.7 |
| 800 × 700 × 100 | 117,810 | 31.8 |
| 1000 × 880 × 120 | 177,186 | 57.4 |
| 1500 × 1380 × 150 | 271,434 | 109.9 |
| 2000 × 1880 × 200 | 365,681 | 197.5 |
Typical supply range
- Rolled rings
- Outside diameters from a few hundred millimetres to several metres, depending on alloy, wall and height
- Cut and machined rings
- Any size that fits within the plate, disc or tube it is cut from
- Condition
- As-forged, rough machined (rectangular section) or finish machined to drawing
- Profile
- Rectangular section or contoured (stepped, flanged) rolled profiles
- Testing
- Tensile by direction, hardness, conductivity, ultrasonic, macro-etch
Machining allowance, distortion and finishing
Distortion control
Quenched rings carry residual stress. Choose stress-relieved tempers (T652, T7352), rough machine, then finish in stages to keep roundness and flatness.
Ovality and flatness
Large thin rings can go oval in handling. Support them on several points and measure on a flat surface plate, not on a single lift point.
Welding
6061, 6082, 5083 and 2219 rings can be welded into assemblies; 7075 and 2014 are generally not fusion welded.
Surface treatment
Anodising, hard anodising and chemical conversion coating suit most ring alloys; 2xxx rings give darker anodic films.
Inspection
Check ID and OD at several angles, height at several points, and grain flow by macro-etch on a test ring for critical parts.
Where aluminium rings are used
- Aerospace and space: fuselage and engine casing rings, propellant tank and inter-stage adapter rings in 2219, 2014 and 7075
- Bearings and drives: lightweight bearing housings, light-duty slewing rings, gear and pulley blanks
- Vacuum and semiconductor: 6061 chamber flanges, sealing rings and wafer-handling rings
- Pipelines and vessels: weld-neck and slip-on flanges, cryogenic vessel rings in 5083
- Industrial machinery: rotary tables, indexing rings, robot joints and optical mounts
- Defence and transport: turret rings, wheel components and rail equipment housings
How to order aluminium rings
- SpecifyFinished drawing or OD × ID × height with tolerances, alloy and temper, route (rolled, cut or welded), condition (as-forged or machined), quantity, standard (ASTM B247, EN 586, AMS) and test requirements.
- QuoteWe confirm alloy, temper, tolerances, certification, packing and delivery terms (EXW, FOB, CIF or DAP) for your destination.
- ProcessRings are forged or cut, heat treated, tested by direction as specified, then rough or finish machined and inspected for size, roundness and flatness.
- DocumentEach delivery carries a mill test certificate to EN 10204 3.1 with the cast analysis and mechanical results; third-party inspection can be arranged on request.
- ShipRings are bagged, supported on pallets or in crates to prevent ovality and shipped by sea or air on EXW, FOB, CIF or DAP terms.
References and standards
- ASTM B247 – Aluminum and Aluminum-Alloy Die Forgings, Hand Forgings, and Rolled Ring Forgings
- SAE AMS 4127 – Aluminum Alloy, Forgings and Rolled or Forged Rings (6061-T6)
- EN 586-2 – Aluminium and aluminium alloys, forgings: mechanical properties and additional property requirements
- ASTM B594 – Ultrasonic inspection of aluminum-alloy wrought products
- ASM Handbook, Volume 2 – Properties and Selection: Nonferrous Alloys and Special-Purpose Materials
Aluminium (aluminum) rings: FAQ
What is the difference between a rolled ring and a cut ring?
A rolled ring is forged from a pierced preform and rolled to size, so the grain runs around the circumference and resists hoop stress and fatigue. A cut ring is profiled out of plate; its grain crosses the ring, the centre is scrap and properties are those of the plate.
How do I calculate the weight of an aluminium ring?
Weight (kg) = π/4 × (OD² − ID²) × height × 2.70 × 10⁻⁶ with dimensions in mm. A 500 × 400 × 50 mm ring weighs about 9.5 kg in 6061; use 2.80 g/cm³ for 7075.
Which alloy is best for an aluminium ring?
6061-T6 for general flanges, vacuum and machinery parts; 7075-T73 or 7050 for high-strength aerospace rings; 2219 for welded cryogenic tank rings; 2618 for elevated temperature; and 5083 for marine and cryogenic service without heat treatment.
Which standard covers aluminium rolled rings?
ASTM B247 covers die forgings, hand forgings and rolled-ring forgings. Aerospace rings are often ordered to SAE AMS specifications such as AMS 4127 for 6061-T6, and European rings to EN 586.
Why do machined aluminium rings distort?
Quenching leaves residual stress that is released as metal is removed. Use stress-relieved tempers such as T652 or T7352, rough machine before finishing, and support large rings evenly.
Can you supply rings machined to drawing?
Yes. Metline supplies rolled or cut rings as-forged, rough machined or finish machined to your drawing, with mill test certificates to EN 10204 3.1 and inspection on request.
Need aluminium rings?
Send the drawing or OD, ID, height, alloy and quantity. We will recommend the route and reply with certification and a delivered price.
