Aluminum 3B21-H19 vs 3B21-O
Aluminum · 3B21 temper comparison
3B21-H19 and 3B21-O are two conditions of the same aluminum grade, 3B21: H19 (strain hardened, extra hard) versus O (annealed). The chemistry is identical, so every difference below comes from the condition. 3B21-H19 is the stronger of the two: yield strength 220 MPa (31.9 ksi) against 52 MPa (7.54 ksi) for 3B21-O, about 4.2 times as much; tensile strength follows at 245 MPa (35.5 ksi) vs 130 MPa (18.9 ksi). In exchange, 3B21-O is the more ductile: elongation 26% versus 2% for 3B21-H19, and 3B21-H19 is harder (60 HB vs 30 HB). 3B21-O runs hotter in service (150°C vs 120°C continuous). On the shop floor, 3B21-H19 machines more easily (fair vs poor) and 3B21-O welds better (excellent vs very good).
3B21-H19Choose it when strength drives the design, or when the part is machined in volume.
3B21-OChoose it when the part is bent, formed or impact-loaded, or when the part sees heat.
3B21-H19 vs 3B21-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 26 GPa3.8 Msi · Bulk Modulus 70 GPa10.2 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 393 J/g169 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).
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
Machinability Rating (AISI 1212 = 100 %)
Weldability
Formability (cold)
Same in both: Brazeability / Solderability 70 / 100 · Polishability 55 / 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 1,200 L/kg144 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.
3B21-H19 vs 3B21-O — frequently asked
Is 3B21-H19 stronger than 3B21-O?
Yes. 3B21-H19 has a typical yield strength of 220 MPa (31.9 ksi) against 52 MPa (7.54 ksi) for 3B21-O — about 4.2 times as much. Tensile strength is 245 MPa (35.5 ksi) vs 130 MPa (18.9 ksi).
Which condition does FabDigit quote by default, H19 or O?
H14 is the default 3B21 condition in the FabDigit quote flow (neither H19 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, 3B21-H19 or 3B21-O?
3B21-H19. Its machinability rates fair (40/100) against poor (25/100) for 3B21-O; for welding the order is 3B21-O first (excellent, 90/100) then 3B21-H19 (very good, 80/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in 3B21-H19 and 3B21-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.