What 1100 Aluminum Sheet Is
1100 aluminum sheet is a commercially pure, non-heat-treatable flat-rolled product with a minimum aluminum content of 99.00%. It sits at the head of the 1xxx purity series and carries the UNS number A91100. Because there are no deliberate alloying additions beyond a small controlled copper range and tight impurity limits, 1100 keeps the properties that make pure aluminum useful: very high formability, easy workability, high thermal and electrical conductivity, and dependable atmospheric corrosion resistance. Density is about 2.71 g/cm3 and the melting range is roughly 643 to 657 Celsius.
The alloy cannot be strengthened by heat treatment the way 6061 or 2024 can. Its mechanical properties come entirely from strain hardening, described by the H tempers of ANSI H35.1 and listed product by product in ASTM B209/B209M. That single fact drives most sourcing decisions: the temper you order fixes the strength, and the thickness tolerance you agree fixes the flatness you will actually receive.
Tempers and Typical Mechanical Properties
Sheet is normally supplied in the O (annealed) temper or in H12 through H18 strain-hardened tempers. The figures below are typical room-temperature values for 1100 sheet, given for guidance only; the certified minimums are those printed on the mill certificate for the specific temper and thickness you order.
| Temper | Tensile strength Rm | Yield strength Rp0.2 | Elongation, 50 mm | Typical duty |
|---|---|---|---|---|
| O | 90 MPa | 35 MPa | 35-45% | Deep drawing, spinning, severe forming |
| H12 | 105 MPa | 90 MPa | 12-20% | General forming with some strength |
| H14 | 125 MPa | 115 MPa | 8-12% | Standard half-hard sheet, most common |
| H16 | 145 MPa | 135 MPa | 5-8% | Stiffer panels, light structural trim |
| H18 | 165 MPa | 150 MPa | 4-6% | Full hard, flat parts without forming |
As the H number rises, strength and springback rise while elongation falls sharply. If a part needs a tight bend radius, order O or H12 rather than trying to bend H18 and then anneal it.
Chemical Composition and Governing Standards
| Element | Limit, mass % |
|---|---|
| Aluminum | 99.00 minimum |
| Silicon plus iron | 0.95 maximum |
| Copper | 0.05-0.20 |
| Manganese | 0.05 maximum |
| Zinc | 0.10 maximum |
| Other elements, each / total | 0.05 / 0.15 maximum |
Product requirements are normally specified against ASTM B209/B209M for sheet and plate, GB/T 3880.2, EN 485-2 or ISO 6361-2. Those standards also hold the dimensional tolerance tables, and the thickness tolerance in particular becomes tighter as the sheet gets thinner, so the same nominal gauge from two suppliers can differ in usable flatness.
Where 1100 Sheet Is Used
Deep-drawn and spun holloware, cookware and catering equipment
Heat exchanger fins, plates and fin stock, where conductivity matters more than strength
Chemical process equipment, liners, drip trays and light storage vessels
Reflectors, nameplates, signage and decorative trim that will be polished or anodized
Transformer strip, cable wrap and general electrical conductor applications
Light-gauge cladding, closures and packaging components
1100 is a poor choice where the part must carry structural load or resist continuous seawater immersion; a 5xxx marine alloy or a heat-treatable 6xxx alloy is the correct answer there. Its real strength is ductility and conductivity at low cost.
How to Specify and Order
State alloy and temper together, for example 1100 H14. Asking only for pure aluminum sheet leaves the strength undefined.
Give dimensions as thickness x width x length, or thickness x width in coil, and state clearly whether you want sheet, cut-to-length blanks or a coil with a specified inside diameter.
Name the tolerance standard, ASTM B209/B209M or GB/T 3880.2, and state the edge condition: mill edge, slit, or deburred.
Describe surface requirements, including whether a protective film or interleaving paper is needed for polished or anodizing-quality faces.
Set the quantity, packing method and marking details, and say whether horizontal or eye-to-sky loading is required for the container.
Ask for the inspection documents you need: a mill test certificate with chemistry and tensile results, dimensional records, and third-party inspection where the end use demands it.
Check the lead time attached to the temper, because full hard H18 is often a make-to-order item while H14 and O are stock tempers.
Incoming Quality Checks
Measure thickness at several points across and along the sheet, not just at one corner, and compare against the tolerance table.
Verify the certificate chemistry against the ordered alloy, and check that the copper range is inside the 1100 window.
Check flatness on a level table, and inspect edges for slitting burrs that will interfere with forming.
Look for handling scratches, roll marks, water staining and edge dents, preferably before the protective film is stripped.
Confirm that the stencil or tag on each bundle matches the certificate number and heat number.
For deep-drawing work, cut a trial blank and form a test part before the balance of the order is released to production.
FAQ
Q: Is 1100 aluminum sheet heat treatable?
No. 1100 is a non-heat-treatable 1xxx alloy. It is strengthened only by strain hardening, which is what the H temper designations describe. Annealing returns it to the soft O condition.
Q: What is the difference between 1100 and 1050 sheet?
Both are commercially pure alloys. 1050 requires 99.50% minimum aluminum and has slightly tighter impurity limits, while 1100 allows 99.00% minimum with a small copper addition. 1050 is preferred for electrical and conductivity work, 1100 for general forming where a little extra strength helps.
Q: Which temper should I choose for deep drawing?
Use O temper. It gives the highest elongation and the lowest yield strength of the range, which lets the metal flow instead of tearing. Parts that need stiffness after forming can be formed in O and then strain hardened or simply designed thicker.
Q: Can 1100 sheet be welded?
Yes. It welds readily by gas tungsten arc and gas metal arc processes using 1100 or 4043 filler. Welded joints are soft and the heat-affected zone loses the strain hardening, so weldments are usually designed for the annealed strength.
Q: Which standard governs thickness tolerance?
ASTM B209/B209M for inch and metric sheet and plate, or GB/T 3880.2 and EN 485-2 for metric supply. The applicable table depends on width and thickness, so quote the standard and the nominal gauge together.
Q: How should 1100 sheet be stored?
Keep bundles dry, off the floor and clear of condensation drip lines. Aluminum does not rust, but moisture trapped between sheets can cause white oxide staining, which is cosmetic but difficult to remove from a polished face.
