Aluminum A356-T4 vs A356-T61
Aluminum · A356 temper comparison
A356-T4 and A356-T61 are two conditions of the same aluminum grade, A356: T4 (solution heat treated and naturally aged) versus T61 (T6 variant, underaged). The chemistry is identical, so every difference below comes from the condition. A356-T61 is the stronger of the two: yield strength 207 MPa (30 ksi) against 110 MPa (16 ksi) for A356-T4, about 88% more; tensile strength follows at 283 MPa (41 ksi) vs 195 MPa (28.3 ksi). In exchange, A356-T4 is the more ductile: elongation 12% versus 8% for A356-T61, and A356-T61 is harder (90 HB vs 60 HB). A356-T61 runs hotter in service (150°C vs 100°C continuous). On the shop floor, A356-T61 machines more easily (very good vs good).
A356-T4Choose it when the part is bent, formed or impact-loaded.
A356-T61Choose it when strength drives the design, or when the part sees heat.
A356-T4 vs A356-T61: 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
Compressive Strength
Shear Strength
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Vickers
Same in both: Elastic (Young's) Modulus 72.4 GPa10.5 Msi · Shear Modulus 26.5 GPa3.8 Msi · Bulk Modulus 70 GPa10.2 Msi · Poisson's Ratio 0.33
Physical
Density and transition temperatures.
Same in both: Density 2.68 g/cm³0.1 lb/in³ · Melting Point (Solidus) 557°C1,035 °F · Liquidus Temperature 613°C1,135 °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 963 J/kg·K0.23 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 21.4 µm/m·K11.9 µin/in·°F · Latent Heat of Fusion 389 J/g167 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 %)
Formability (cold)
Same in both: Weldability 80 / 100 · Castability 95 / 100 · Brazeability / Solderability 40 / 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 kg CO₂/kg · Embodied Water 1,150 L/kg138 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.
A356-T4 vs A356-T61 — frequently asked
Is A356-T61 stronger than A356-T4?
Yes. A356-T61 has a typical yield strength of 207 MPa (30 ksi) against 110 MPa (16 ksi) for A356-T4 — about 88% more. Tensile strength is 283 MPa (41 ksi) vs 195 MPa (28.3 ksi).
Which condition does FabDigit quote by default, T4 or T61?
Specify the condition in the material field or the drawing note; FabDigit prices the quote for the state you call out.
Which is easier to machine, A356-T4 or A356-T61?
A356-T61. Its machinability rates very good (70/100) against good (60/100) for A356-T4.
Ready to make it?
Upload a CAD file and FabDigit prices the part in A356-T4 and A356-T61 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.