Aluminium Discs and Circle Blanks
Aluminium discs (also called circles or circle blanks) are round blanks cut from sheet or coil and made to be deep drawn, spun or pressed into cookware, lamp reflectors, tanks, traffic signs and cans. The usual grades are 1050, 1060, 1070, 1100, 3003 and 5052 in soft O or lightly hardened H12/H14 tempers. Metline supplies discs in a wide range of diameters and thicknesses, with controlled earing and surface, to customers worldwide.
- Grades
- 1050, 1060, 1100, 3003, 5052
- Tempers
- O, H12, H14, H22
- Thickness
- 0.3 – 6 mm (typical)
- Standards
- ASTM B209 · EN 485 · EN 941
What are aluminium discs?
A circle blank is the starting point for any round, hollow aluminium product. The blank is clamped and drawn or spun over a tool until the flat disc becomes a pan, pot, reflector or cylinder, so the way the metal stretches matters more than its strength.
Discs are made by rolling sheet to the final gauge, annealing it to a controlled temper, and blanking or cutting circles from it. They may be produced from DC (direct-chill) cast hot-rolled stock, which gives fine grain and very uniform properties for deep drawing and anodising, or from CC (continuous cast) stock, which is more economical and suits general spinning and shallow pressing. After blanking the circles are often annealed again so they are fully soft and free of blanking strain.
Because drawing magnifies any defect, buyers specify not only alloy, size and temper but also grain size, earing, surface cleanliness and edge condition. A disc that is too hard or has coarse grain will crack or show an "orange-peel" surface; strong directional properties cause the cup rim to form waves, called ears, that must be trimmed off.
Disc alloys, tempers and properties
| Alloy and temper | Tensile strength | Elongation (typ.) | Typical uses |
|---|---|---|---|
| 1050-O / 1060-O | 65 – 95 MPa | 30 – 40 % | Deep-drawn cookware, reflectors, chemical vessels |
| 1070-O | 60 – 90 MPa | 30 – 40 % | Lighting reflectors, high-purity anodised parts |
| 1100-O | 75 – 105 MPa | 30 – 35 % | Kitchen utensils, pressure cooker bodies, traffic signs |
| 1050 / 1100-H12, H14 | 95 – 145 MPa | 5 – 15 % | Spun lamp shades, shallow pressings |
| 3003-O | 95 – 135 MPa | 25 – 30 % | Stronger cookware, pressure cookers, tanks |
| 3003-H14 | 140 – 180 MPa | 5 – 8 % | Lids, signs, rigid shallow parts |
| 5052-O / H32 | 170 – 260 MPa | 12 – 20 % | Pressure vessels, marine parts, high-strength cookware |
Tensile ranges follow EN 485-2 and ASTM B209 limits for the O and H tempers over typical disc gauges; exact limits depend on thickness. Elongation values are typical for gauges around 1 – 3 mm.
1050 and 1060 are the default for deep-drawn utensils because they are extremely ductile and conduct heat well (about 220 – 230 W/m·K). 3003 adds manganese for roughly 20 % more strength with similar formability, which allows thinner walls in pressure cookers. 5052 is used where stiffness, strength or seawater resistance matter more than draw depth.
Disc sizes and weights
Typical supply range
- Thickness
- 0.3 – 6 mm; thicker plate circles on request
- Diameter
- About 80 – 1000 mm; larger circles cut from plate
- Tempers
- O, H12, H14, H16, H18, H22, H24
- Surface
- Mill finish, clean and oil-free; bright or brushed on request
- Edge
- Blanked, sheared or trimmed; deburred for spinning
We confirm the diameter and gauge combination, temper and earing limit with each quotation.
A disc weighs π/4 × D² × t × 2.71 g/cm³. With D and t in millimetres, weight in grams = 0.002128 × D² × t. The table gives quick values; use the circle weight calculator for any size.
| Diameter (mm) | 1.0 mm (g) | 2.0 mm (g) | 3.0 mm (g) |
|---|---|---|---|
| 100 | 21 | 43 | 64 |
| 150 | 48 | 96 | 144 |
| 200 | 85 | 170 | 255 |
| 250 | 133 | 266 | 399 |
| 300 | 192 | 383 | 575 |
| 400 | 341 | 681 | 1022 |
| 500 | 532 | 1064 | 1596 |
| 600 | 766 | 1532 | 2299 |
Earing, grain size and other quality checks
| Check | Why it matters | How it is measured |
|---|---|---|
| Earing | Waviness at the cup rim must be trimmed; high earing wastes metal | Cupping test, % ear height |
| Grain size | Coarse grain gives orange peel and cracks during drawing | Metallography or grain-size comparison |
| Ductility | Determines the draw depth before splitting | Tensile test and Erichsen cupping index |
| Flatness | Distorted blanks feed poorly and wrinkle | Measured on a surface table |
| Surface and cleanliness | Oil, oxide and scratches show after anodising or coating | Visual and wipe tests |
| Diameter and thickness | Affects tooling fit and final wall thickness | Callipers and micrometer |
Earing comes from crystallographic texture in the sheet, and it is controlled at the rolling and annealing stage, not at blanking. A low-earing material for deep-drawn cookware is typically specified to a few per cent ear height. If your parts are spun rather than drawn, earing is less critical but edge quality and uniform softness become more important.
Standards and equivalents
| Purpose | Standard |
|---|---|
| Sheet and plate properties (from which discs are cut) | ASTM B209; EN 485-2 |
| Circles for cookware | EN 941 – circles and circle stock for culinary utensils |
| Chemical composition | Aluminum Association registrations; EN 573-3 |
| Food-contact composition | EN 602 |
| Japan / China / India | JIS H4000; GB/T 3880; IS 737 / IS 21 (utensil grades) |
| Inspection certificate | EN 10204 type 3.1 |
Where aluminium discs are used
- Cookware: frying pans, saucepans, pressure cookers, non-stick and hard-anodised pans, kettles
- Lighting: spun lamp shades and reflectors in 1050, 1070 and 1100
- Packaging: aerosol cans, collapsible tubes and bottle caps (thicker discs are called slugs)
- Road signs: circular traffic signs in 1100, 3003 or 5052
- Industrial: tank ends, pressure vessel heads, ventilation and fan components
- Electronics and decoration: speaker parts, nameplates and decorative panels
How to order aluminium discs
- SpecifyAlloy, temper, diameter, thickness, tolerances, quantity, forming process and any earing or grain-size limits.
- QuoteWe confirm availability, DC or CC stock route, certification and terms (EXW, FOB, CIF or DAP).
- ProduceDiscs are blanked, annealed if required, cleaned and inspected.
- DocumentMill test certificate to EN 10204 3.1 with chemistry and mechanical properties.
- ShipStacked with interleaving, wrapped against moisture and packed in wooden cases or on pallets.
References and standards
- ASTM B209 – Aluminum and Aluminum-Alloy Sheet and Plate
- EN 941 – Circles and circle stock for the production of culinary utensils: specifications
- EN 485-2 – Sheet, strip and plate: mechanical properties
- EN 602 – Wrought products: chemical composition of semi-finished products for food contact
- The Aluminum Association – International Alloy Designations and Chemical Composition Limits (Teal Sheets)
Aluminium (aluminum) discs and circles: FAQ
Which aluminium alloy is best for cookware discs?
1050 and 1060 in O temper are most common for deep-drawn pans because they are very ductile and conduct heat well. 3003-O is used for stronger, thinner-walled cookware and pressure cookers.
What is earing in aluminium circles?
Earing is the wavy rim that forms when a disc is deep drawn into a cup, caused by directional properties in the rolled sheet. Low-earing material reduces trimming waste and is specified for deep-drawn parts.
What is the difference between DC and CC aluminium circles?
DC circles are cut from direct-chill cast, hot-rolled sheet with a fine, uniform grain, preferred for deep drawing and anodising. CC circles come from continuously cast strip and are more economical for general spinning and pressing.
How do I calculate the weight of an aluminium disc?
Weight in grams = 0.002128 × diameter² × thickness, with dimensions in millimetres. A 300 mm disc 2 mm thick weighs about 383 g.
Can you supply discs for spinning lamp shades?
Yes. 1050, 1070 and 1100 discs in O or H12 temper with deburred edges are the usual choice for spun reflectors and lamp shades.
Need aluminium circles?
Send the alloy, temper, diameter, thickness and forming process. We will reply with availability, quality limits and a delivered price.
