Aluminum 8021-H18 vs 8021-O
Aluminum · 8021 temper comparison
8021-H18 and 8021-O are two conditions of the same aluminum grade, 8021: H18 (strain hardened, full hard) versus O (annealed). The chemistry is identical, so every difference below comes from the condition. 8021-H18 is the stronger of the two: yield strength 145 MPa (21 ksi) against 35 MPa (5.08 ksi) for 8021-O, about 4.1 times as much; tensile strength follows at 160 MPa (23.2 ksi) vs 85 MPa (12.3 ksi). In exchange, 8021-O is the more ductile: elongation 25% versus 2% for 8021-H18, and 8021-H18 is harder (50 HV vs 23 HV). 8021-O runs hotter in service (150°C vs 110°C continuous). On the shop floor, 8021-H18 machines more easily (32 vs 20 out of 100).
8021-H18Choose it when strength drives the design, or when the part is machined in volume.
8021-OChoose it when the part is bent, formed or impact-loaded, or when the part sees heat.
8021-H18 vs 8021-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, Vickers
Same in both: Elastic (Young's) Modulus 69 GPa10 Msi · Shear Modulus 26 GPa3.8 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) 650°C1,202 °F · Liquidus Temperature 660°C1,220 °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 900 J/kg·K0.21 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 23.6 µm/m·K13.1 µin/in·°F · Latent Heat of Fusion 395 J/g170 BTU/lb · Min Service Temperature -196°C-321 °F
Electrical
Conductivity and insulation.
Electrical Conductivity
Electrical Resistivity
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Galvanic Potential (seawater, vs SCE) -0.78 V · Corrosion Resistance 65 / 100
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 40 / 100 · Polishability 55 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 205 MJ/kg88,134 BTU/lb · Embodied Carbon (primary production) 12.5 kg CO₂/kg · Embodied Water 1,150 L/kg138 gal/lb · Typical Recycled Content 20%
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.
8021-H18 vs 8021-O — frequently asked
Is 8021-H18 stronger than 8021-O?
Yes. 8021-H18 has a typical yield strength of 145 MPa (21 ksi) against 35 MPa (5.08 ksi) for 8021-O — about 4.1 times as much. Tensile strength is 160 MPa (23.2 ksi) vs 85 MPa (12.3 ksi).
Which condition does FabDigit quote by default, H18 or O?
H14 is the default 8021 condition in the FabDigit quote flow (neither H18 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, 8021-H18 or 8021-O?
8021-H18, by a small margin. Both rate poor for machinability — 32/100 against 20/100 for 8021-O; for welding the order is 8021-O first (fair, 45/100) then 8021-H18 (fair, 40/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in 8021-H18 and 8021-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.