3003 is the alloy to reach for when the shape of the part matters more than its strength. It deep-draws and spins further than almost any other wrought aluminium, survives outdoor and food-contact service without a coating, and welds with ordinary shop equipment. What it will not do is deliver structural strength or machine like a free-cutting grade.
That trade-off is the whole story of the alloy, and most specification errors come from seeing only half of it. A buyer picks 3003 for a tank, a duct or a radiator core, then asks the same material to carry load or hold a tolerance in a machining centre, which it cannot do.
What 3003 Aluminium Alloy Is
3003 aluminium is a non-heat-treatable Al-Mn alloy in the 3xxx series, registered as UNS A93003 and known in Europe as EN AW-3003, or AlMn1Cu. Manganese at 1.0–1.5% is the only deliberate addition, and it lifts strength by roughly 20% over commercially pure 1100 without sacrificing formability or corrosion resistance.
There is no ageing step, so the mill creates the entire strength by cold reduction. That single fact explains both the temper system and the main service limitation: any later annealing or welding step hands strength back locally.
The alloy was standardised in the 1930s and is now among the highest-volume rolled aluminium grades in the world. Supply is deep, pricing is stable, and it is held in more tempers than any other 3xxx grade.
Chemical Composition and Standards
The limits below are the registered composition for 3003 and are shared by ASTM B209 and EN 573-3. All figures are weight percent.
| Element | Limit (wt %) |
| Silicon (Si) | ≤ 0.60 |
| Iron (Fe) | ≤ 0.70 |
| Copper (Cu) | 0.05 – 0.20 |
| Manganese (Mn) | 1.00 – 1.50 |
| Zinc (Zn) | ≤ 0.10 |
| Titanium (Ti) | ≤ 0.05 |
| Others, each | ≤ 0.05 |
| Others, total | ≤ 0.15 |
| Aluminium (Al) | Remainder |
This table is standard and complete, so there is nothing in it to negotiate. Two points do catch buyers out, though.
Magnesium and chromium are not specified separately for 3003 in either standard, so any residual falls under the 0.05% “others, each” limit. Some mill certificates print Mg ≤ 0.05 and Cr ≤ 0.05 to make that implicit limit explicit, which is why two datasheets can look different while describing exactly the same alloy.
The same material carries different designations across systems, and the product standard changes with the form you buy.
| System | Designation | Governing product standards |
| AA / UNS | 3003 / A93003 | ASTM B209 (sheet, plate), B210 (drawn tube), B211 (bar, rod, wire), B221 (extruded profiles) |
| EN | EN AW-3003 / AlMn1Cu (DIN 3.0517) | EN 573-3 (chemistry), EN 485 (rolled), EN 754 (drawn), EN 755 (extruded) |
| ISO | AlMn1Cu | ISO 6361 |
| JIS | A3003 | JIS H4000 / H4040 / H4080 |
| GB | 3003 | GB/T 3190, GB/T 3880 |
If a drawing says only “3003” and nothing else, confirm the product form before price is agreed. Rolled and extruded stock carry different standards, different temper definitions and different mechanical minimums, and the gap is wide enough to change a design.
Mechanical Properties by Temper
Temper sets these numbers far more than chemistry does. Cold reduction from the annealed state roughly doubles tensile strength and removes most of the ductility, and every step of that is deliberate.
| Property | 3003-O (annealed) | 3003-H14 (half hard) | 3003-H18 (full hard) |
| Tensile strength, Rm (MPa) | 95 – 130 | 140 – 180 | ≥ 185 |
| Yield strength, Rp0.2 (MPa) | ≥ 35 | ≥ 115 | ≥ 165 |
| Elongation (%) | ≥ 25 | ≥ 5 | ≥ 3 |
| Hardness (HB) | ≈ 28 | ≈ 40 | ≈ 55 |
For flat-rolled work, H14 is the working default and O is the temper you specify on purpose. Pick O when the part will be deep drawn, spun or tightly bent after supply, H14 when it must hold shape through light forming, and H18 when it will not be formed at all. Details of the half-hard route, its bending radii and its forming limits sit in our 3003-H14 guide.
Minimum values are thickness-dependent, so a figure quoted without a gauge is not usable. ASTM B209 lowers the elongation minimum as sheet gets thinner, and EN 485-2 publishes slightly higher H14 numbers than ASTM does: a 145–185 MPa tensile range with a 125 MPa proof minimum. State the governing standard on the order and read the certified values from the inspection document supplied with the heat.
Physical Properties
These are the values behind most thermal and weight calculations. Density and modulus are effectively fixed, while the conductivity figures shift slightly with temper.
| Property | Value |
| Density | 2.73 g/cm³ |
| Melting range | ≈ 640 – 655 °C |
| Thermal conductivity | ≈ 160 – 190 W/(m·K), highest in the annealed temper |
| Electrical conductivity | ≈ 40 – 44 % IACS |
| Thermal expansion, 20–100 °C | 23.1 µm/(m·K) |
| Elastic modulus | ≈ 69.5 GPa |
| Annealing range | 350 – 400 °C |
Density is the figure that usually decides a project. At 2.73 g/cm³, 3003 carries roughly one third of the weight of steel, which is why it displaces galvanised sheet in tanks, ducting and jacketing. Thermal conductivity is good but well below copper, so the alloy competes on weight and cost rather than on raw heat transfer.
Choosing a Temper
The temper you name fixes the balance between strength and how much forming the part can still take. Most volume sits in O, H14 and H22; the others exist for one specific process or one specific stress.
| Temper | What it is | Typical use |
| O | Annealed, fully soft | Deep drawing, spinning, complex stampings |
| H12 | Quarter hard | General forming where a little strength helps |
| H14 | Half hard | Roofing, siding, tanks, cookware, general fabrication |
| H16 | Three-quarter hard | Structural panels, signage |
| H18 | Full hard | Flat panels with no post-supply forming |
| H22 | Strain-hardened, then partly annealed | Parts formed after delivery, where H14 would crack |
| H112 | As-fabricated, no strain-hardening control | Thick plate and heavy-gauge structural work |
H22 is the temper buyers overlook most often. It delivers strength close to H14 with noticeably better ductility, which matters when the forming happens at your plant rather than at the mill and the part has to bend without cracking.
Where 3003 Is Chosen — and Where It Is Not
3003 wins when four requirements arrive together: easy forming, outdoor-grade corrosion resistance, straightforward welding, and a low cost per kilogram. Remove any one of them and another alloy usually takes the job.
Specify 3003 when:
- The part is deep drawn, spun or severely bent, and finished thickness is set by the die rather than by stress.
- The assembly is brazed, or it is a radiator, condenser, evaporator or cooling plate.
- Service is outdoor, marine-atmosphere, food-contact or mildly chemical, and you would rather not add a coating.
- Volume is high and a stable, widely available alloy matters more than the last few percent of strength.
Move to another grade when:
- Design stress exceeds the H18 ceiling, which 5052 in H32 or a heat-treatable alloy handles easily.
- The part is machined rather than formed.
- A cold-worked temper has to keep full strength across a weld.
- Decorative anodising is required from continuously cast stock.
Machinability is the limitation that surprises buyers most, because 3003 looks like a general-purpose metal on paper. The grade is too soft and ductile to form a clean chip: it smears, builds up on the cutting edge and leaves a poor finish. For turned, milled or drilled parts, 6061-T6, 6262 or 2011 are the correct choices, and the extra material cost is normally recovered in cycle time.
Applications of 3003 Aluminum
Heat Exchangers, Radiators and Brazing Sheet
The single largest use of 3003 is as the core layer of clad brazing sheet. A typical build is 4343/3003/4343, or 4045 on one or both faces, where the 4xxx skin melts in the furnace while the 3003 core stays solid.
That structure is what makes a brazed heat exchanger possible without added filler. The skin flows into the joint by capillary action, and the core carries the strength and holds the fluid channels to dimension.
Parts built this way include car radiators, condensers, evaporators, charge-air coolers, heater cores, air-conditioning coil fins, and the liquid-cooling plates used in battery packs and energy storage. Plain 3003 sheet and fin stock cover the lower-cost end of the same market, where brazing duty is light but stamping and forming still decide the temper.
Building, Roofing and HVAC
3003 is a default cladding material for roofing, siding, gutters, flashing and wall panels. It weathers without a protective coating, and it rolls and folds into the profiles those systems need.
The same properties put it into ductwork, insulated pipe jacketing, HVAC housings and drainage goods. Where a project wants colour, 3003 aluminium sheet takes paint or a pre-painted coil finish.
Transport and Automotive
Transport uses the alloy where weight and fabrication cost matter more than strength: fuel tanks, oil pans, trailer and truck body panels, battery trays and non-structural brackets.
The same sector consumes it by the tonne in vehicle heat exchangers, which is the largest automotive application by volume. Forecast and fabrication demand here usually decides whether a mill order runs in O or H14.
Food, Chemical and General Fabrication
Food-contact and mildly corrosive duty is a natural fit: cookware, food-processing trays, storage tanks, light chemical equipment and fresh-water piping components.
Beyond that, the grade covers general sheet-metal work — enclosures, signage, nameplates, furniture trim, lighting reflectors and formed electrical housings — wherever moderate strength is enough and a clean surface is wanted.
How 3003 Compares
Against the alloys it is most often weighed against, 3003 sits in the middle of the non-heat-treatable group and well below the heat-treatable ones.
AlloyStrengthened byStrength at a common temperBest reason to pick it1100Cold workH14 ≈ 110 – 145 MPaMaximum conductivity and corrosion purity3003Cold workH14 ≈ 140 – 180 MPaThe general-purpose balance3004Cold workH34 ≈ 215 – 240 MPaHigher-strength sheet and can stock5052Cold workH32 ≈ 210 – 260 MPaMarine and pressure service6061Heat treatmentT6 ≥ 290 MPaStructural and machined parts
The decision against 6061 is about process rather than properties. If the part is formed from flat sheet in volume, 3003 is cheaper and more ductile; if it is machined, welded into a loaded frame or asked to carry stress, 6061 wins and 3003 cannot follow.
The full side-by-side, including corrosion and welding behaviour, sits in our 3003 vs 6061 comparison. Where the question is which rolled alloy suits a container or a panel, the 3104 vs 3003 vs 3004 sheet comparison works through the same decision.
Conclusion
3003 is a general-purpose Al-Mn sheet alloy, and its trade-off is a low strength ceiling: H18 reaches only about 185 MPa tensile, well under 5052-H32 or 6061-T6, and the grade machines poorly. It earns its place through formability, corrosion resistance, weldability and brazing behaviour, not through load capacity.
We supply 3003 as sheet, plate, coil, strip, tube, bar and wire in O, H12, H14, H18, H22 and H112, in standard sizes or made to your drawing, at a low MOQ with a 10–60 day lead time. Every order ships with a mill test certificate, and SGS reports are available on request.
Send us your 3003 temper, thickness and drawing, and we will confirm stock, price and lead time.
Frequently Asked Questions
What is the highest strength I can design to in 3003?
About 185 MPa tensile in H18 under ASTM B209, the hardest temper the grade is rolled to. H14 and H22 sit lower and trade strength for formability. If the design stress climbs past the H18 ceiling, move to 5052-H32 or a heat-treatable alloy.
What is the minimum order quantity and lead time for 3003?
Standard tempers and sizes ship from stock; anything outside that range runs as low-MOQ production, typically 10–60 days, depending on alloy, dimensions and processing. Sheet, plate, coil, strip, tube, bar and wire are all supplied.
What do I need to send for a 3003 quote?
Four details settle most enquiries:
- Temper and thickness, because the mechanical minimums depend on both.
- Product form — sheet, plate, coil, strip, tube, bar or wire.
- The governing standard, ASTM B209 or its EN equivalent.
- Whether a mill test certificate is enough or third-party SGS testing is also required.
What documents come with a 3003 order?
A mill test certificate reporting the actual chemistry and mechanical results for the lot. SGS reports are available on request at extra testing cost. EN 10204 3.2 adds an independent countersignature where a project requires one.
