Solid forged disc
A plain disc with no bore, for gear blanks, covers and wheels that will be fully machined.
Upset-forged discs and blanks
Forged Aluminium Discs and Custom Blanks
A forged aluminium disc is a round blank made by upsetting a billet between flat or shaped dies, so its grain spreads out radially and the metal is dense right through. That gives better strength, toughness and fatigue life in the plane of the disc than a circle cut from plate, which is why forged discs are used for wheels, gear blanks, flanges, turntables and pressure covers. Metline supplies forged discs, hubs and blanks in 6061, 7075, 2024, 7050, 5083 and other alloys, as forged, heat treated or machined, worldwide.
- Forms
- Solid discs, bored discs, hubs, custom blanks
- Alloys
- 6061 · 7075 · 2024 · 7050 · 5083
- Condition
- As forged, heat treated or machined
- Standards
- ASTM B247 · EN 586 · AMS
What is a forged aluminium disc?
Forged discs (also called pancakes or upset blanks) start as a length of cast or forged bar. The billet is heated and pressed along its axis so that it shortens and spreads into a disc. Further operations can add a raised hub, a recess or a pierced centre hole before heat treatment and machining.
Upsetting changes the metal in a useful way. Grain that ran along the billet is turned outward, so the disc has similar properties in every radial and circumferential direction, which is what a rotating or pressure-loaded part needs. Porosity left from casting is closed, and the cast structure is broken down. A disc sawn or cut from thick plate, by comparison, has the rolling direction running straight across it, so its properties vary around the circumference and the centre of very thick plate is the least worked metal.
Forged discs also save metal. A disc cut from a square plate wastes the corners, and a disc machined from a large bar wastes the outside. A forged disc can be made close to the finished diameter and thickness with only a machining allowance, and features such as hubs can be formed rather than machined from solid.
Types of forged discs and blanks
Disc with centre hole
Pierced or pre-bored to reduce machining for bearing seats, flanges and couplings. Larger bores become rings.
Disc with raised hub
Hub and web forged in one piece with continuous grain flow, for wheels, pulleys and drive flanges that carry torque through the hub.
Recessed or stepped disc
Recesses, steps and grooves forged close to shape to save metal and machining time.
Forged hub
A thick, compact disc for shafts, wheels and rotating assemblies, with bores and splines machined afterwards.
Large-diameter disc
Heavy flanges, turntables and base plates where cut plate would be too thin or lack through-thickness properties.
Alloys for forged discs
| Alloy | Common tempers | Why it is chosen | Typical disc parts |
|---|---|---|---|
| 6061 | T6, T652 | Good strength, corrosion resistance and weldability; economical | Wheels, flanges, covers, vacuum chamber parts |
| 6082 | T6 | European alternative to 6061, slightly stronger | Wheel hubs, pulleys, machinery discs |
| 7075 | T6, T652, T73, T7352 | Very high strength and fatigue resistance | Motorsport and aircraft wheels, gear blanks, high-load flanges |
| 7050 | T74, T7452 | High strength in thick discs; low quench sensitivity, good SCC resistance | Thick aerospace discs and heavy-duty blanks |
| 2024 | T4, T6, T852 | High fatigue strength under repeated loading | Aircraft wheel halves, rotating discs |
| 2014 | T6 | High strength, good forgeability | Heavily loaded wheels and discs |
| 2618 | T61 | Keeps strength up to about 200 – 250 °C | Compressor wheels, impellers, hot-running discs |
| 5083 | O, H112 | Excellent seawater resistance and weldability; good at cryogenic temperatures | Marine covers, chemical-plant and cryogenic end caps |
Choose the temper with machining and service in mind. Thick discs that will be machined heavily, such as wheel blanks with deep pockets, are best ordered in a stress-relieved temper (T652, T7352 or T7452) to limit distortion. For alloy detail see 6061, 7075 and 2024 forgings.
Typical properties of forged disc alloys
Typical values are shown for comparison. In a forged disc the radial and circumferential (tangential) properties are similar; the axial direction, through the thickness, is usually the weakest and is the one to specify for thick, pressure-loaded parts. Guaranteed minimums come from the order specification.
| Alloy and temper | Tensile strength | Yield strength (0.2 %) | Elongation |
|---|---|---|---|
| 6061-T6 | 310 MPa / 45 ksi | 276 MPa / 40 ksi | 12 % |
| 6082-T6 | about 330 MPa | about 280 MPa | 10 – 12 % |
| 2014-T6 | 483 MPa / 70 ksi | 414 MPa / 60 ksi | 13 % |
| 2024-T4 | 469 MPa / 68 ksi | 324 MPa / 47 ksi | 19 % |
| 2618-T61 | 440 MPa / 64 ksi | 370 MPa / 54 ksi | 10 % |
| 7075-T73 | 505 MPa / 73 ksi | 435 MPa / 63 ksi | 13 % |
| 7075-T6 | 572 MPa / 83 ksi | 503 MPa / 73 ksi | 11 % |
| 5083-O | about 290 MPa | about 145 MPa | about 22 % |
How forged aluminium discs are made
- BilletCast and homogenised or pre-forged bar is sawn to the weight of the disc plus allowance. To avoid buckling, the starting height is normally kept below about two to three times the billet diameter.
- HeatingThe billet and dies are preheated; forging temperatures are roughly 380 – 480 °C depending on alloy.
- UpsettingThe billet is pressed along its axis to the target thickness. Large reductions, sometimes with intermediate draw-out and re-upset, give a well-worked structure.
- ShapingHubs, recesses and steps are formed in shaped dies; centre holes are pierced. Wide-bore parts continue to ring rolling.
- Heat treatmentSolution treatment, quench and ageing; compression stress relief for T652, T7352 or T7452.
- Machining and inspectionFacing, turning and boring as ordered, followed by testing and certification.
For high-volume parts such as vehicle wheels, discs are forged in closed dies that form the spokes and hub directly. See aluminium die forgings for that route.
Sizes and weights of forged discs
Forged discs are made to order from the finished-part envelope: from small blanks a little over 100 mm diameter up to large discs for flanges and turntables, with thickness to suit. Feasible size depends on alloy, weight and specification; send your drawing and we confirm the forged size and allowance.
| Disc size (D × t) | 6061 weight (kg) | 7075 weight (kg) |
|---|---|---|
| Ø 200 × 30 mm | 2.5 | 2.6 |
| Ø 300 × 50 mm | 9.5 | 9.9 |
| Ø 400 × 60 mm | 20.4 | 21.2 |
| Ø 500 × 80 mm | 42.4 | 44.1 |
| Ø 600 × 100 mm | 76.3 | 79.5 |
| Ø 800 × 120 mm | 162.9 | 169.5 |
| Ø 1000 × 150 mm | 318.1 | 331.0 |
| Ø 1200 × 200 mm | 610.7 | 635.6 |
Theoretical weight of a solid disc: kg = π/4 × D² × t (mm) × density (g/cm³) / 1,000,000, using 2.70 g/cm³ for 6061 and 2.81 g/cm³ for 7075. Our disc weight calculator handles other sizes and bores.
Delivery conditions, machining and tolerances
As forged
Black surface with allowance on every face, for customers who machine in house.
Heat treated
Forged and heat treated to the ordered temper, ready for machining.
Rough machined
Faced and turned to a reduced allowance, which also allows ultrasonic inspection to a finer class.
Finish machined
Turned, bored and drilled to drawing, with tolerances set by the machined features rather than the forging.
Typical inspection plan
- Chemistry
- Heat analysis traceable to the billet
- Mechanical tests
- Tensile tests in tangential, radial or axial directions as specified, from prolongations or extra discs
- Hardness and conductivity
- On each disc or by sampling
- Ultrasonic
- To ASTM B594 or AMS-STD-2154 after rough machining
- Dimensional
- Gauges or CMM for machined discs
- Certificate
- EN 10204 3.1; third-party inspection on request
Where forged aluminium discs are used
| Sector | Typical parts | Common alloys |
|---|---|---|
| Automotive and motorsport | Wheel blanks, hubs, brake carriers, pulleys | 6061-T6, 6082-T6, 7075 |
| Aerospace | Wheel halves, gear blanks, engine and structural discs | 2014-T6, 2024, 7075-T73, 7050-T74 |
| Turbomachinery | Compressor wheels, impellers, fan hubs | 2618-T61, 7075 |
| Industrial machinery | Turntables, flywheels, rollers, indexing discs | 6061-T6, 7075-T6 |
| Process and pressure equipment | Blind flanges, covers, vessel heads, valve discs | 6061-T6, 5083 |
| Marine and cryogenic | Hatch covers, end caps, cryogenic flanges | 5083 |
| Semiconductor and vacuum | Chamber lids and base plates | 6061-T6 |
A typical example is a heavy turntable or base plate above 100 mm thick. Cut from plate, the centre of the thickness has the lowest properties; a forged disc of the same size is worked through its thickness and gives more consistent results in the axial direction.
Forged discs compared with discs cut from plate or bar
| Factor | Forged disc | Disc cut from plate | Slice cut from bar |
|---|---|---|---|
| Grain orientation | Radial, similar in all in-plane directions | Rolling direction across the disc | Axial; weakest in the disc plane |
| Through-thickness properties | Good, fully worked | Lower at the centre of thick plate | Varies |
| Fatigue and impact | Highest | Good | Lower |
| Material yield | High (near net) | Low (corners scrapped) | Medium |
| Lead time and cost | Higher for small quantities | Short, economical | Short, economical |
| Best for | Rotating, pressure and critical parts | Covers, fixtures, non-critical parts | Small discs and prototypes |
For thin, non-critical round parts, aluminium circles cut from sheet or plate are cheaper and faster. Choose a forged disc when the part rotates, holds pressure, is thick, or must meet a forging specification.
How to order forged aluminium discs
- SpecifyFinished drawing, alloy and temper, quantity, specification and revision, and which faces are critical.
- TestingTest directions (tangential, radial, axial), UT class, hardness or conductivity, third-party inspection.
- ProposalWe return forged dimensions, machining allowance, heat-treatment route and inspection plan.
- Production and documentsForging, heat treatment, machining and testing, with an EN 10204 3.1 certificate and reports.
- ShippingDiscs separated and crated for export with corrosion protection; EXW, FOB, CIF or DAP.
References and standards
- ASTM B247 – Aluminum and Aluminum-Alloy Die Forgings, Hand Forgings, and Rolled Ring Forgings
- EN 586-1/-2/-3 – Aluminium and aluminium alloys: forgings
- ASTM B594 – Ultrasonic Inspection of Aluminum-Alloy Wrought Products
- The Aluminum Association – International Alloy Designations and Chemical Composition Limits
- ASM Handbook, Vol. 14A – Metalworking: Bulk Forming
Forged aluminium (aluminum) discs: frequently asked questions
Why use a forged disc instead of cutting a circle from plate?
A forged disc has radial grain flow and is worked through its thickness, so strength and fatigue properties are consistent around the circumference and through the section. A plate-cut disc has the rolling direction running across it and weaker centre properties in thick sizes.
Which alloy is best for a forged wheel or gear blank?
6061-T6 or 6082-T6 for most vehicle and industrial wheels, 7075 for motorsport and high-load gear blanks, and 2014 or 2024 for aircraft wheels to the relevant specification.
What sizes of forged discs can you supply?
Discs are forged to order from the finished-part size, from small blanks a little over 100 mm diameter to large flanges and turntables. Send the drawing and we confirm the forged size.
Can forged discs be supplied with a centre hole?
Yes. Discs can be pierced or bored; when the bore becomes large relative to the outside diameter, a rolled ring is usually the more economical route.
Which temper limits distortion during machining?
Stress-relieved tempers such as 6061-T652, 7075-T7352 or 7050-T7452, in which the disc is compressed after quenching to remove most residual stress.
Are forged discs ultrasonically tested?
They can be, to ASTM B594 or AMS-STD-2154. Testing after rough machining allows a finer acceptance class.
Need forged aluminium discs?
Send the drawing, alloy, temper and quantity. We will propose forged dimensions, an inspection plan and a delivered price.
