Aluminum AC3A vs AC8B
Aluminum · grade comparison
Aluminum AC3A and AC8B are both aluminum grades. AC8B is the stronger of the two: yield strength 235 MPa (34.1 ksi) against 75 MPa (10.9 ksi) for AC3A, about 3.1 times as much; tensile strength follows at 280 MPa (40.6 ksi) vs 165 MPa (23.9 ksi). In exchange, AC3A is the more ductile: elongation 6% versus 1% for AC8B, and AC8B is harder (110 HB vs 50 HB). AC3A is lighter (2.66 g/cm³ vs 2.76 g/cm³ for AC8B) and AC8B is stiffer (82 GPa vs 71 GPa). On the shop floor, AC8B machines more easily (50 vs 40 out of 100) and AC3A welds better (very good vs poor).
AC3AChoose it when the part is bent, formed or impact-loaded, or when weight is the constraint.
AC8BChoose it when strength drives the design, or when the part sees heat.
AC3A vs AC8B: 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.
Elastic (Young's) Modulus
Shear Modulus
Bulk Modulus
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Shear Strength
Fatigue Strength (Endurance Limit)
Hardness, Brinell
Compressive Strength
Same in both: Poisson's Ratio 0.33 · Fracture Toughness (K_IC) 15 MPa·√m13.7 ksi·√in · Charpy V-Notch Impact (RT) 3 J2.2 ft·lbf
Physical
Density and transition temperatures.
Density
Melting Point (Solidus)
Same in both: Liquidus Temperature 582°C1,080 °F
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Thermal Expansion (CTE, 20–100 °C)
Max Service Temperature (continuous)
Min Service Temperature
Same in both: Specific Heat Capacity 963 J/kg·K0.23 BTU/lb·°F · Latent Heat of Fusion 389 J/g167 BTU/lb
Electrical
Conductivity and insulation.
Electrical Conductivity
Electrical Resistivity
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Galvanic Potential (seawater, vs SCE)
Corrosion Resistance
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Machinability Rating (AISI 1212 = 100 %)
Weldability
Formability (cold)
Castability
Brazeability / Solderability
Polishability
Sustainability
Primary-production footprint per kilogram.
Embodied Water
Typical Recycled Content
Same in both: Embodied Energy (primary production) 200 MJ/kg85,985 BTU/lb · Embodied Carbon (primary production) 12 kg CO₂/kg
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Specific Stiffness (E / density)
Modulus of Resilience
Thermal Diffusivity
Thermal Shock Resistance Index
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.
Manufacturing and finishing
| Capability | AC3A | AC8B |
|---|---|---|
| Default condition | — | — |
| Relative cost | $$ Standard | $$ Standard |
| Min. machined wall | — | — |
| Best machined surface | — | — |
Both take the same 4 finishes: Electroless Nickel (EN), Epoxy Coating, Gold Plating, Silver Plating.
AC3A vs AC8B — frequently asked
Is AC8B stronger than AC3A?
Yes. AC8B has a typical yield strength of 235 MPa (34.1 ksi) against 75 MPa (10.9 ksi) for AC3A — about 3.1 times as much. Tensile strength is 280 MPa (40.6 ksi) vs 165 MPa (23.9 ksi).
Which is cheaper, AC3A or AC8B?
Both sit in the same relative cost tier ($$, standard); the part price will be decided by machining time, tolerance and quantity rather than by the material.
Which is easier to machine, AC3A or AC8B?
AC8B, by a small margin. Both rate fair for machinability — 50/100 against 40/100 for AC3A; for welding the order is AC3A first (very good, 80/100) then AC8B (poor, 22/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in AC3A and AC8B 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.