Ordering flat-rolled aluminium fixes three variables at once: alloy, temper and tolerance. The grades below cover most industrial sheet demand, from the unalloyed 1050 and 1100 through manganese-bearing 3003 to the magnesium alloys 5052 and 5083, and the heat-treatable 6061.
Composition per ASTM B209 and GB/T 3190-2020
| Alloy | Aluminium, min | Principal alloying additions |
|---|---|---|
| 1050 | 99.50% | Unalloyed |
| 1100 | 99.00% | Cu 0.05-0.20% |
| 3003 | Remainder | Mn 1.0-1.5%, Cu 0.05-0.20% |
| 5052 | Remainder | Mg 2.2-2.8%, Cr 0.15-0.35% |
| 5083 | Remainder | Mg 4.0-4.9%, Mn 0.40-1.0%, Cr 0.05-0.25% |
| 6061 | Remainder | Mg 0.8-1.2%, Si 0.40-0.80%, Cu 0.15-0.40%, Cr 0.04-0.35% |
What O, H14 and H24 Mean in Practice
O is the fully annealed temper: lowest strength, highest elongation, and the correct choice when a part is deep drawn or spun in one operation. H14 is strain hardened to quarter-hard without subsequent annealing. H24 is the same level of work hardening followed by a partial anneal, which is the usual route for magnesium-bearing alloys because it stabilises properties and improves ductility. For one alloy, moving from O to H14 typically doubles tensile strength while elongation falls to roughly a third of the annealed value.
Typical Strengths and Where Each Alloy Fits
| Alloy and temper | Tensile / yield, MPa | Typical use |
|---|---|---|
| 1050-O | 76 / 28 (typical) | Deep-drawn holloware, reflectors |
| 1100-H14 | 124 / 117 (typical) | Chemical equipment, heat shields |
| 3003-H14 | 152 / 145 (typical) | General fabrication, panels, ducting |
| 5052-H32 | 215 / 160 (ASTM B209 minimum) | Marine and transport sheet |
| 5083-H116 | 275 / 215 (ASTM B209 minimum) | Ship hulls, cryogenic tanks |
| 6061-T6 | 290 / 240 (ASTM B209 minimum) | Structural profiles and plate |
Values marked as ASTM B209 minimum are specification limits rather than expected results, so production material usually tests higher. Mechanical properties for sheet and strip are also tabulated in GB/T 3880.2-2012 and EN 485-2, with dimensions and tolerances in GB/T 3880.3.
Selecting Between Them
Where chloride corrosion governs, 5052 or 5083 is the correct answer and 3003 is not, because the magnesium-bearing alloys resist salt spray and seawater without coating; ASTM B928 covers the marine plate grades. Where formability governs and strength is secondary, 1050 or 1100 gives the deepest draw. Where the part is machined and heat treated after forming, 6061 is supplied in T4 for forming and aged to T6 afterwards, while the 5xxx and 3xxx grades cannot be strengthened by heat treatment at all.
Supply, Tolerances and Inspection
Sheet ships with mill certificates covering chemistry, tensile properties and dimensions. Buyers should specify alloy, temper, thickness and width tolerance class, edge condition (mill edge, trimmed or slit), surface finish and interleaving or protective film, since these variables affect yield loss more than the alloy itself does. Standard export packing with edge protection is used for coil and cut-to-length sheet.
Frequently Asked Questions
Q: Can 5052 replace 3003 in a fuel tank?
A: Yes, and it is often preferred: 5052-H32 has 215 MPa minimum tensile strength against roughly 152 MPa typical for 3003-H14, and much better resistance to chloride pitting, at a higher price per kilogram.
Q: Which of these alloys can be anodised?
A: 1050, 1100, 3003, 5052 and 6061 all anodise well. High-magnesium 5083 gives a darker, less uniform finish and is normally left mill finish or painted instead.
Q: Is 5083 weldable?
A: Yes, with 5183 or 5356 filler. Because 5083 is not heat treated, it keeps most of its strength in the heat-affected zone, which is why it dominates welded marine structures.
Q: What is the real difference between H14 and H24 sheet?
A: Both are quarter-hard. H24 is partially annealed after rolling, which gives higher elongation and more stable properties in service, and it is the temper normally supplied in the 5xxx series.
Q: Which temper bends to the tightest radius?
A: O temper bends to a near-zero radius. Quarter-hard tempers need a radius related to thickness, and 5052 tolerates tighter radii than 6061-T6, which is usually bent in T4 and aged to T6 afterwards.