Aluminum Coil Alloys Compared: 1100, 3003, 3105, and 5052
The alloy question usually arrives as a substitution question. A supplier is out of 3003 and offers 3105. A drawing calls for 5052 and the quote comes back high. Someone asks whether 6061 would work because it sounds stronger.
Those are not interchangeable answers, and the differences between some of these alloys are small enough that guessing feels safe. It usually is not. Here is what separates the coil alloys, with the numbers behind them.
The Short Answer
- 1100 is commercially pure aluminum, at least 99.00 percent. The softest and most formable, the weakest, and the best conductor. Specified when forming ease, surface quality, or reflectivity matters more than strength.
- 3003 adds 1.0 to 1.5 percent manganese. The general purpose workhorse, noticeably stronger than 1100 while keeping most of its formability.
- 3105 carries less manganese (0.30 to 0.8 percent) plus 0.20 to 0.8 percent magnesium. Slightly higher strength minimums than 3003 in the same temper, and it is widely used for painted architectural coil, siding, and rainware.
- 5052 carries 2.2 to 2.8 percent magnesium. A clear step up in strength, with strong corrosion resistance including good performance in marine atmospheres.
- 6061 is heat treatable and belongs to a different conversation. More on that below.
Composition limits above are from ASTM B209.
Mechanical Properties Compared
The table below shows ASTM B209 specified limits for sheet in the 0.020 to 0.050 inch range, which covers many common architectural and general fabrication coil gauges. These are the limits the material must meet, not typical mill results. Actual values on a certificate normally sit above the minimum.
| Alloy and temper | Tensile strength, ksi | Yield strength, min ksi | Elongation, min % |
|---|---|---|---|
| 1100-H14 | 16.0 to 21.0 | 14.0 | 3 to 4 |
| 3003-H14 | 20.0 to 26.0 | 17.0 | 3 to 4 |
| 3105-H14 | 22.0 to 29.0 | 18.0 | 1 to 2 |
| 3105-H25 | 23.0 min | 19.0 | 3 to 4 |
| 5052-H32 | 31.0 to 38.0 | 23.0 | 5 |
| 6061-T6 | 42.0 min | 35.0 | 8 to 10 |
Approximate metric equivalents: 1 ksi is about 6.9 MPa, so 3003-H14 runs roughly 138 to 179 MPa tensile with a 117 MPa yield minimum, and 5052-H32 roughly 214 to 262 MPa with a 159 MPa yield minimum.
Two things stand out. The gap between 3003 and 3105 is narrow, around 2 to 3 ksi at the same temper designation. The gap between the 3xxx alloys and 5052 is not narrow at all, roughly 50 percent more tensile strength.
Temper Does as Much Work as Alloy
Comparing alloys without stating temper produces meaningless numbers. The same alloy annealed and full hard behaves very differently.
For the non-heat-treatable alloys used in coil, strength comes from cold work and is reduced by annealing. In the annealed condition, 1100-O carries an 11.0 to 15.5 ksi tensile range, 3003-O runs 14.0 to 19.0, 3105-O runs 14.0 to 21.0, and 5052-O runs 25.0 to 31.0. Every one of those sits well below the same alloy at H14 or H32, and every one has far higher elongation.
That is the tradeoff. Harder tempers give higher strength, higher hardness, and more resistance to permanent deformation. Softer tempers give ductility and forming capability.
One clarification worth making, because it gets stated wrong often: temper does not meaningfully change aluminum’s elastic modulus. All of these alloys sit near 69 GPa regardless of temper. A harder temper resists denting and permanent set, but it does not make a panel of the same alloy and geometry measurably stiffer in the engineering sense. If deflection is the problem, the answers are gauge, geometry, and support spacing, not temper.
The H1x and H2x distinction matters on the shop floor. H1x is strain hardened only. H2x is strain hardened and then partially annealed, restoring some ductility while retaining much of the cold-worked strength. Compare 3105-H14 at 1 to 2 percent minimum elongation against 3105-H24 at 3 to 4 percent, at the same 22.0 ksi tensile minimum and 18.0 ksi yield minimum. Same strength floor, more room to bend. This is why H2x tempers are common on coil that has to be roll formed or brake formed after coating.
ASTM B209 also allows the supplier to ship H2x in place of the equivalent H1x, and the other way around, unless the purchase order excludes it. If your forming operation depends on the ductility, say so on the order rather than assuming.
3105 vs 3003: The Substitution You Will Actually Be Offered
This is the most common swap in coil, and in most painted architectural work it is a reasonable one.
3105 is leaner on manganese than 3003, with magnesium added. In practice it lands slightly above 3003 on strength minimums at the same temper and slightly below it on formability. 3105 is widely used for painted coil, residential siding, roofing, and rain carrying goods. 3003 is the broader general fabrication alloy.
Where the swap needs a second look:
- Welded components. Both alloys are weldable, but confirm the alloy, temper, filler selection, and welding process before approving a substitution rather than treating the two as drop-in equivalents.
- Deep forming or tight bends. Check the elongation minimum for the specific temper, not the alloy in general. 3105-H14 has a low minimum.
- Drawings that name the alloy for compliance reasons. If a spec or submittal says 3003, a substitution needs approval, not a judgment call.
3003 vs 5052
This one is not close. 5052 has roughly 50 percent more tensile strength and about a third more yield strength at comparable tempers, and its 2.2 to 2.8 percent magnesium gives it better corrosion resistance, particularly in saltwater and marine atmospheres.
You pay for that in cost and in formability. Where the application does not benefit from 5052’s higher strength, fatigue performance, or corrosion resistance, a 3xxx alloy is usually the more economical answer. Where it does, including tanks, enclosures, transportation panels, and chemical exposure, the premium is doing real work.
5005 sits between the two on magnesium at 0.50 to 1.1 percent and is worth asking about where you want a better anodizing response than 3xxx without going all the way to 5052.
5052 vs 6061
This comparison gets searched constantly, and the honest answer is that the two are rarely competing for the same job.
6061 is heat treatable. Its strength comes from solution treatment and aging rather than cold work, which is why 6061-T6 reaches a 42.0 ksi tensile minimum and 35.0 ksi yield minimum, beyond anything in the 3xxx or 5xxx range above. 6061 sheet exists and is covered by ASTM B209, but the alloy is far more commonly supplied as extrusion, plate, and bar, and it is rarely the first choice for the architectural and general fabrication coil applications discussed here.
So if you are sizing a structural bracket, 6061 may well be the right material and coil may be the wrong form. If you are specifying roofing, gutters, shutter slats, cladding, panels, or trim, the real decision sits between 3003, 3105, and 5052.
What the Mill Behind the Coil Actually Rolls
Coil capability is narrower than the full alloy catalog, and it is worth checking against your spec before you commit to it.
Primealux Alloys supplies aluminum coil produced by Orbit Aluminum Industries, an integrated producer in Aqaba, Jordan. Orbit’s rolling range covers 1xxx, 3xxx, and 5xxx series alloys at 0.20 to 2.00 mm thick and up to 1650 mm wide, with coil weight up to 10 tons at maximum width and temper supplied to requirement, confirmed at quote stage.
Casting, rolling, and coil coating run on the same site, so material can move from mill finish to painted coil without leaving for outside finishing. The two lines have different limits, which matters if you are specifying wide painted coil: rolling goes to 1650 mm, while the coating line runs up to 1350 mm wide and 1.60 mm thick. Coating systems include PE, HDPE, PVDF, and PUPA among others, in any RAL or custom match. Recycled content coil is available on select alloys and traceable to the cast batch.
Getting the Spec Right Before You Request a Quote
Alloy alone is not a specification. A quotable coil spec answers:
- Alloy. 1xxx, 3003, 3105, 5052, 5005.
- Temper, and whether H1x or H2x is acceptable.
- Thickness and width, with tolerances if they are tight.
- Forming process. Roll formed, brake formed, deep drawn, or welded. This drives the temper more than anything else.
- Finish. Mill, stucco or embossed, or prepainted, and the coating system if painted.
- Environment and service life. Coastal, industrial, interior.
- Quantity and coil dimensions, including inner diameter and maximum coil weight your uncoiler can handle.
If you know the application but not the alloy, work backward from the part. Primealux Alloys publishes an application to spec selector that returns a recommended alloy, temper, and coating for common coil applications, which is a faster starting point than reading property tables cold. Material supplied through Primealux Alloys is produced to order by the mill against the submitted spec rather than pulled from standing warehouse stock, so the spec you send is the spec that gets made.
One Last Check
Ask for the mill certificate and read it against the standard you specified. ASTM B209 and the applicable EN standards define composition, mechanical property, and dimensional requirements for a given product and temper, and a certificate showing actual tensile, yield, and elongation for your lot tells you what you are forming. On a job where the part has to bend without cracking, that document is more useful than any alloy comparison table, including this one.
