Aluminum 2A21-O vs 2A21-T62
Aluminum · 2A21 temper comparison
2A21-O and 2A21-T62 are two conditions of the same aluminum grade, 2A21: O (annealed) versus T62 (T6, heat treated by the user). The chemistry is identical, so every difference below comes from the condition. 2A21-T62 is the stronger of the two: yield strength 275 MPa (39.9 ksi) against 80 MPa (11.6 ksi) for 2A21-O, about 3.4 times as much; tensile strength follows at 390 MPa (56.6 ksi) vs 175 MPa (25.4 ksi). In exchange, 2A21-O is the more ductile: elongation 18% versus 11% for 2A21-T62, and 2A21-T62 is harder (115 HB vs 45 HB). 2A21-O conducts heat better (170 W/m·K vs 121 W/m·K). On the shop floor, 2A21-T62 machines more easily (good vs fair).
2A21-OChoose it when the part is bent, formed or impact-loaded.
2A21-T62Choose it when strength drives the design, or when the part is machined in volume.
2A21-O vs 2A21-T62: propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all aluminum grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
How to read these bars
- One bar per material. A full bar is the highest value among all aluminum grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Reduction in Area
Shear Strength
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
Hardness, Brinell
Hardness, Vickers
Same in both: Elastic (Young's) Modulus 73 GPa10.6 Msi · Shear Modulus 27 GPa3.9 Msi · Bulk Modulus 75 GPa10.9 Msi · Poisson's Ratio 0.33
Physical
Density and transition temperatures.
Same in both: Density 2.84 g/cm³0.1 lb/in³ · Melting Point (Solidus) 543°C1,009 °F · Liquidus Temperature 643°C1,189 °F
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Same in both: Specific Heat Capacity 864 J/kg·K0.21 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 22.3 µm/m·K12.4 µin/in·°F · Latent Heat of Fusion 389 J/g167 BTU/lb · Max Service Temperature (continuous) 250°C482 °F · Min Service Temperature -196°C-321 °F
Electrical
Conductivity and insulation.
Electrical Conductivity
Electrical Resistivity
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Corrosion Resistance
Same in both: Galvanic Potential (seawater, vs SCE) -0.66 V
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Machinability Rating (AISI 1212 = 100 %)
Weldability
Formability (cold)
Same in both: Brazeability / Solderability 15 / 100 · Polishability 60 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 210 MJ/kg90,284 BTU/lb · Embodied Carbon (primary production) 12.5 kg CO₂/kg · Embodied Water 1,100 L/kg132 gal/lb · Typical Recycled Content 15%
Strength versus weight
Yield strength against density for every aluminum grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.
2A21-O vs 2A21-T62 — frequently asked
Is 2A21-T62 stronger than 2A21-O?
Yes. 2A21-T62 has a typical yield strength of 275 MPa (39.9 ksi) against 80 MPa (11.6 ksi) for 2A21-O — about 3.4 times as much. Tensile strength is 390 MPa (56.6 ksi) vs 175 MPa (25.4 ksi).
Which condition does FabDigit quote by default, O or T62?
T4 is the default 2A21 condition in the FabDigit quote flow (neither O nor T62). The other condition is available on request or by drawing note — specify it in the material field or the part notes and the quote is priced for it.
Which is easier to machine, 2A21-O or 2A21-T62?
2A21-T62. Its machinability rates good (62/100) against fair (40/100) for 2A21-O.
Ready to make it?
Upload a CAD file and FabDigit prices the part in 2A21-O and 2A21-T62 side by side — material, machining time, tolerance and finish in one quote. Certified material data ships with the order on request.
Typical handbook values for the conditions named above, normalised for comparison. Hardness on non-Brinell scales is converted approximately for charting only. Request certified data with your order for design-critical properties.