Aluminum 222.0-O vs 222.0-T551
Aluminum · 222.0 temper comparison
222.0-O and 222.0-T551 are two conditions of the same aluminum grade, 222.0: O (annealed) versus T551 (permanent mold cast, stabilized). The chemistry is identical, so every difference below comes from the condition. 222.0-T551 is the stronger of the two: yield strength 241 MPa (35 ksi) against 138 MPa (20 ksi) for 222.0-O, about 75% more; tensile strength follows at 255 MPa (37 ksi) vs 186 MPa (27 ksi). In exchange, 222.0-O is the more ductile: elongation 1% versus 0.5% for 222.0-T551, and 222.0-T551 is harder (115 HB vs 80 HB). On the shop floor, 222.0-T551 machines more easily (80 vs 70 out of 100).
222.0-OChoose it when the part is bent, formed or impact-loaded.
222.0-T551Choose it when strength drives the design, or when the part is machined in volume.
222.0-O vs 222.0-T551: 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 74 GPa10.7 Msi · Shear Modulus 28 GPa4.1 Msi · Bulk Modulus 74 GPa10.7 Msi · Poisson's Ratio 0.33
Physical
Density and transition temperatures.
Same in both: Density 2.95 g/cm³0.11 lb/in³ · Melting Point (Solidus) 521°C970 °F · Liquidus Temperature 627°C1,161 °F
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Same in both: Specific Heat Capacity 963 J/kg·K0.23 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 22.6 µm/m·K12.6 µin/in·°F · Latent Heat of Fusion 389 J/g167 BTU/lb · Max Service Temperature (continuous) 230°C446 °F · Min Service Temperature -195°C-319 °F
Electrical
Conductivity and insulation.
Electrical Conductivity
Same in both: Electrical Resistivity 5.2×10⁻⁸ Ω·m2.05 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Galvanic Potential (seawater, vs SCE) -0.72 V · Corrosion Resistance 25 / 100
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Same in both: Weldability 20 / 100 · Castability 35 / 100 · Brazeability / Solderability 15 / 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) 12.5 kg CO₂/kg · Embodied Water 1,100 L/kg132 gal/lb · Typical Recycled Content 50%
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.
222.0-O vs 222.0-T551 — frequently asked
Is 222.0-T551 stronger than 222.0-O?
Yes. 222.0-T551 has a typical yield strength of 241 MPa (35 ksi) against 138 MPa (20 ksi) for 222.0-O — about 75% more. Tensile strength is 255 MPa (37 ksi) vs 186 MPa (27 ksi).
Which condition does FabDigit quote by default, O or T551?
T61 is the default 222.0 condition in the FabDigit quote flow (neither O nor T551). 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, 222.0-O or 222.0-T551?
222.0-T551, by a small margin. Both rate very good for machinability — 80/100 against 70/100 for 222.0-O.
Ready to make it?
Upload a CAD file and FabDigit prices the part in 222.0-O and 222.0-T551 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.