Aluminium Rolled Ring Forgings
A rolled ring forging is a seamless ring made by piercing a forged disc and then rolling it between a driven main roll and an internal mandrel until the wall thins and the diameter grows to size. Because the metal flows around the circumference, the grain follows the ring, giving better fatigue and toughness than a ring cut from plate or a welded band. This guide explains the process, alloys, tempers, properties and how to specify rings; Metline supplies aluminium rolled rings worldwide.
- Process
- Radial-axial ring rolling
- Alloys
- 2014, 2219, 6061, 6082, 7050, 7075, 5083
- Tempers
- T6, T652, T73, T7352, T74
- Standard
- ASTM B247 · EN 586
Why rings are rolled instead of cut or welded
There are three common ways to make an aluminium ring: cut it from plate, roll and weld a strip into a band, or forge it seamless. Cutting from plate wastes most of the metal and leaves the grain running straight across the ring. Welded bands have a heat-affected zone with reduced strength. A rolled ring has neither problem.
During ring rolling, metal is squeezed between rolls and flows in the circumferential direction, so the grain wraps around the ring. Loads in rotating and pressure-retaining parts mostly act around the circumference, so the strongest direction of the forging lines up with the main stresses. Material yield is also high because the ring is rolled close to its final shape, leaving only a modest machining allowance.
For these reasons rolled rings are standard for bearing housings and races, slewing rings, flanges, gear blanks, rocket and launch-vehicle tank rings, aircraft engine casings and large seals.
The rolled ring forging process step by step
- Cut the billetA cast and homogenised billet, or forged bar, is sawn to the weight needed for the finished ring plus allowance.
- HeatThe billet is heated to the alloy's forging range, typically a few hundred degrees Celsius below melting, and held to an even temperature.
- Upset and pierceOn a press the billet is upset into a pancake, then a punch pierces the centre to make a thick-walled donut preform.
- Ring rollingThe preform is placed over a mandrel. The driven main roll presses the wall against the mandrel, thinning it and enlarging the diameter, while axial cone rolls control ring height.
- Size and shapeRolling stops when the target diameter is reached. Profiled rolls can produce contoured cross-sections closer to the finished shape.
- Heat treatHeat-treatable alloys are solution treated, quenched, optionally cold-compressed or expanded for stress relief, then aged.
- Machine and inspectRings are rough or finish machined, ultrasonically tested and dimensionally inspected.
Temperature control is critical with aluminium. The forging window is narrow, the metal cools quickly against the rolls, and overheating risks incipient melting in high-alloy grades such as 2014 and 7075. Rings are often reheated between preforming and rolling, and roll speeds are matched to the alloy.
Aluminium alloys for rolled rings
| Alloy | Common tempers | Strength class | Typical uses |
|---|---|---|---|
| 6061 | T6, T652 | Medium–high | Structural rings, housings, flanges, vacuum equipment |
| 6082 | T6 | Medium–high | European equivalent of 6061; transport and machinery rings |
| 2014 | T4, T6, T652 | High | Heavy-duty structural and aerospace rings, wheels |
| 2024 | T4, T6 | High | Rotating parts needing fatigue resistance |
| 2219 | T6, T852 | High | Cryogenic tank rings and high-temperature parts; weldable |
| 7075 | T6, T73, T7352 | Very high | Aerospace rings; T73 tempers for stress-corrosion resistance |
| 7050 | T74, T7452 | Very high | Thick-section aerospace rings with low quench sensitivity |
| 5083 | O, H111, H112 | Medium | Marine and cryogenic rings, non-heat-treatable |
The "52" tempers (T652, T7352, T7452, T852) indicate that the ring was stress relieved after quenching by a controlled amount of cold compression or expansion. Like the stretched "51" tempers of plate, they make the ring much more stable during machining, which matters for thin-walled rings that must stay round.
Mechanical properties of aluminium forgings
The table shows ASTM B247 minimum values for die forgings of moderate thickness as a reference point. Rolled rings are covered by the same standard, with minimums given by test direction (tangential, axial, radial) and thickness; tangential properties are usually the highest because they follow the grain.
| Alloy & temper | Min. tensile | Min. yield (0.2 %) | Min. elongation |
|---|---|---|---|
| 6061-T6 | 260 MPa | 240 MPa | 7 % |
| 2014-T6 | 450 MPa | 385 MPa | 6 % |
| 2219-T6 | 400 MPa | 260 MPa | 8 % |
| 7075-T6 | 515 MPa | 440 MPa | 7 % |
| 7075-T73 | 455 MPa | 385 MPa | 7 % |
| 7050-T74 | 495 MPa | 425 MPa | 7 % |
Reference minimums summarised from ASTM B247 for die forgings; rolled ring values by direction and thickness differ and are stated on the mill certificate. 5083 rings are supplied to the properties of the agreed specification.
Tolerances, inspection and documentation
Typical requirements
- Size range
- From small rings of a few hundred millimetres to rings several metres in diameter, depending on alloy and section
- As-rolled tolerance
- Machining allowance on all faces; final tolerances achieved by machining
- Roundness and concentricity
- Specified on the drawing; stress-relieved tempers help hold them after machining
- Ultrasonic testing
- ASTM B594 or AMS-STD-2154, class agreed with the buyer
- Heat treatment
- AMS 2770 for aerospace orders, or as required by ASTM B247 / EN 586
- Certification
- EN 10204 3.1 certificate; 3.2 with third-party witness on request
Ask for test coupons from a prolongation of the ring or from a sacrificial ring in the same lot, and state the test directions. For aerospace work, the drawing usually requires a first-article inspection that includes grain-flow macro-etch.
Rolled rings compared with other ring routes
| Route | Grain flow | Material yield | Best for |
|---|---|---|---|
| Rolled ring forging | Circumferential, follows the ring | High | Medium to very large rings in volume |
| Open-die forged ring (saddle or mandrel forging) | Good, partly circumferential | Medium | Thick-walled or short rings, small quantities |
| Closed-die forged ring | Follows the die contour | High once dies exist | Small rings in high volumes |
| Ring cut from plate | Straight across the ring | Low | Prototypes and small, lightly loaded parts |
| Rolled and welded band | Interrupted at the weld | High | Low-stress rings where a weld is acceptable |
For a full overview of forged and rolled ring routes see our forged ring and rolled ring page, and for bearing, gear and flange blanks the seamless rolled rings guide.
Where aluminium rolled rings are used
- Aerospace: engine and nacelle rings, fuselage joint rings, bearing seats and seal carriers
- Space: propellant tank Y-rings and adapter rings in 2219 and 2195-type alloys
- Marine and offshore: thruster and propulsion rings, flanges in 5083 and 6061
- Energy: seal and support rings for generators and turbines
- Rail and automotive: lightweight gear and bearing housings, wheel rings
- Machinery: slewing rings, large flanges and rotating tables where weight saving reduces inertia
References and standards
- ASTM B247 – Standard Specification for Aluminum and Aluminum-Alloy Die Forgings, Hand Forgings, and Rolled Ring Forgings
- EN 586-2 – Aluminium and aluminium alloys, forgings: mechanical properties
- ASTM B594 – Standard Practice for Ultrasonic Inspection of Aluminum-Alloy Wrought Products
- SAE AMS 2770 – Heat Treatment of Wrought Aluminum Alloy Parts
- ASM Handbook, Vol. 14A – Metalworking: Bulk Forming (ring rolling)
Aluminium (aluminum) rolled ring forgings: FAQs
What is a rolled ring forging?
A seamless ring made by piercing a forged preform and rolling it between a driven roll and a mandrel until it reaches the required diameter, wall and height.
Why is a rolled ring stronger than a ring cut from plate?
Rolling aligns the grain around the circumference, which is the direction of the main loads in most rings. A ring cut from plate has grain running straight across it, so some sections are loaded across the grain.
What does T652 mean?
Solution heat treated, stress relieved by controlled cold compression after quenching, and artificially aged. It reduces distortion when the ring is machined.
Which aluminium alloy is best for rolled rings?
6061-T6 for general structural rings, 2014 or 7075 for high strength, 7075-T73 or 7050-T74 where stress corrosion matters, 2219 for cryogenic or high-temperature service, and 5083 for marine use.
Which standard covers aluminium rolled rings?
ASTM B247 covers die, hand and rolled ring forgings; EN 586 covers forgings in Europe. Aerospace orders often add AMS heat-treatment and ultrasonic requirements.
Can rolled rings be supplied machined?
Yes. Rings can be supplied as forged, rough machined or finish machined to drawing, with ultrasonic and dimensional reports.
Need aluminium rolled rings?
Send the drawing, alloy, temper, quantity and inspection requirements. We reply with feasibility, certification and a delivered price.
