Aluminum 356-T51 vs 356-T6
Aluminum · 356 temper comparison
356-T51 and 356-T6 are two conditions of the same aluminum grade, 356: T51 (T5, stress relieved by stretching) versus T6 (solution heat treated and artificially aged). The chemistry is identical, so every difference below comes from the condition. 356-T6 is the stronger of the two: yield strength 186 MPa (27 ksi) against 138 MPa (20 ksi) for 356-T51, about 35% more; tensile strength follows at 262 MPa (38 ksi) vs 172 MPa (24.9 ksi). 356-T6 is the more ductile: elongation 5% versus 2% for 356-T51, and 356-T6 is harder (80 HB vs 60 HB). 356-T51 runs hotter in service (175°C vs 150°C continuous).
356-T51Choose it when the part sees heat.
356-T6Choose it when strength drives the design, or when the part is bent, formed or impact-loaded.
356-T51 vs 356-T6: 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
Same in both: Elastic (Young's) Modulus 72.4 GPa10.5 Msi · Shear Modulus 27 GPa3.9 Msi · Bulk Modulus 71 GPa10.3 Msi · Poisson's Ratio 0.33
Physical
Density and transition temperatures.
Same in both: Density 2.67 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) 21.5 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 78 / 100 · Castability 95 / 100 · Brazeability / Solderability 30 / 100 · Polishability 45 / 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 60%
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.
356-T51 vs 356-T6 — frequently asked
Is 356-T6 stronger than 356-T51?
Yes. 356-T6 has a typical yield strength of 186 MPa (27 ksi) against 138 MPa (20 ksi) for 356-T51 — about 35% more. Tensile strength is 262 MPa (38 ksi) vs 172 MPa (24.9 ksi).
Which condition does FabDigit quote by default, T51 or T6?
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, 356-T51 or 356-T6?
356-T6. Its machinability rates very good (70/100) against good (65/100) for 356-T51.
Ready to make it?
Upload a CAD file and FabDigit prices the part in 356-T51 and 356-T6 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.