Aluminum AC3A vs AC4A
Aluminum · grade comparison
Aluminum AC3A and AC4A are both aluminum grades. AC4A is the stronger of the two: yield strength 200 MPa (29 ksi) against 75 MPa (10.9 ksi) for AC3A, about 167% more; tensile strength follows at 260 MPa (37.7 ksi) vs 165 MPa (23.9 ksi). In exchange, AC3A is the more ductile: elongation 6% versus 3% for AC4A, and AC4A is harder (90 HB vs 50 HB). AC4A conducts heat better (150 W/m·K vs 130 W/m·K). On the shop floor, AC4A machines more easily (50 vs 40 out of 100) and AC3A welds better (very good vs good).
AC3AChoose it when the part is bent, formed or impact-loaded, or when it will be welded.
AC4AChoose it when strength drives the design, or when the part is machined in volume.
AC3A vs AC4A: 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)
Fracture Toughness (K_IC)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Compressive Strength
Same in both: Elastic (Young's) Modulus 71 GPa10.3 Msi · Shear Modulus 26.5 GPa3.8 Msi · Bulk Modulus 70 GPa10.2 Msi · Poisson's Ratio 0.33
Physical
Density and transition temperatures.
Density
Melting Point (Solidus)
Liquidus Temperature
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Thermal Expansion (CTE, 20–100 °C)
Latent Heat of Fusion
Same in both: Specific Heat Capacity 963 J/kg·K0.23 BTU/lb·°F · Max Service Temperature (continuous) 150°C302 °F · 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) -0.83 V · Corrosion Resistance 58 / 100
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Machinability Rating (AISI 1212 = 100 %)
Weldability
Castability
Brazeability / Solderability
Same in both: Formability (cold) 10 / 100 · Polishability 45 / 100
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Carbon (primary production)
Embodied Water
Same in both: Typical Recycled Content 70%
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 | AC4A |
|---|---|---|
| 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 AC4A — frequently asked
Is AC4A stronger than AC3A?
Yes. AC4A has a typical yield strength of 200 MPa (29 ksi) against 75 MPa (10.9 ksi) for AC3A — about 167% more. Tensile strength is 260 MPa (37.7 ksi) vs 165 MPa (23.9 ksi).
Which is cheaper, AC3A or AC4A?
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 AC4A?
AC4A, 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 AC4A (good, 65/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in AC3A and AC4A 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.