Aluminum 3A21-H22 vs 3A21-O
Aluminum · 3A21 temper comparison
3A21-H22 and 3A21-O are two conditions of the same aluminum grade, 3A21: H22 (strain hardened and partially annealed, quarter hard) versus O (annealed). The chemistry is identical, so every difference below comes from the condition. 3A21-H22 is the stronger of the two: yield strength 110 MPa (16 ksi) against 42 MPa (6.09 ksi) for 3A21-O, about 162% more; tensile strength follows at 130 MPa (18.9 ksi) vs 110 MPa (16 ksi). In exchange, 3A21-O is the more ductile: elongation 33% versus 14% for 3A21-H22, and 3A21-H22 is harder (35 HB vs 28 HB). 3A21-O runs hotter in service (200°C vs 150°C continuous) and 3A21-O conducts heat better (193 W/m·K vs 163 W/m·K).
3A21-H22Choose it when strength drives the design.
3A21-OChoose it when the part is bent, formed or impact-loaded, or when the part sees heat.
3A21-H22 vs 3A21-O: 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
Shear Strength
Fatigue Strength (Endurance Limit)
Hardness, Brinell
Same in both: Elastic (Young's) Modulus 69 GPa10 Msi · Shear Modulus 25 GPa3.6 Msi · Bulk Modulus 69 GPa10 Msi · Poisson's Ratio 0.33
Physical
Density and transition temperatures.
Same in both: Density 2.73 g/cm³0.1 lb/in³ · Melting Point (Solidus) 643°C1,189 °F · Liquidus Temperature 654°C1,209 °F
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Max Service Temperature (continuous)
Same in both: Specific Heat Capacity 893 J/kg·K0.21 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 23.2 µm/m·K12.9 µin/in·°F · Latent Heat of Fusion 390 J/g168 BTU/lb · Min Service Temperature -250°C-418 °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) -0.83 V
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Weldability
Formability (cold)
Same in both: Machinability Rating (AISI 1212 = 100 %) 25% · Brazeability / Solderability 90 / 100 · Polishability 45 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 200 MJ/kg85,985 BTU/lb · Embodied Carbon (primary production) 13 kg CO₂/kg · Embodied Water 1,100 L/kg132 gal/lb · Typical Recycled Content 35%
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.
3A21-H22 vs 3A21-O — frequently asked
Is 3A21-H22 stronger than 3A21-O?
Yes. 3A21-H22 has a typical yield strength of 110 MPa (16 ksi) against 42 MPa (6.09 ksi) for 3A21-O — about 162% more. Tensile strength is 130 MPa (18.9 ksi) vs 110 MPa (16 ksi).
Which condition does FabDigit quote by default, H22 or O?
H14 is the default 3A21 condition in the FabDigit quote flow (neither H22 nor O). 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, 3A21-H22 or 3A21-O?
3A21-H22. Its machinability rates fair (35/100) against poor (30/100) for 3A21-O.
Ready to make it?
Upload a CAD file and FabDigit prices the part in 3A21-H22 and 3A21-O 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.