Aluminum 355-T6 vs 355-T7
Aluminum · 355 temper comparison
355-T6 and 355-T7 are two conditions of the same aluminum grade, 355: T6 (solution heat treated and artificially aged) versus T7 (solution heat treated and overaged (stabilized)). The chemistry is identical, so every difference below comes from the condition. 355-T7 is the stronger of the two: yield strength 250 MPa (36.3 ksi) against 180 MPa (26.1 ksi) for 355-T6, about 39% more; tensile strength follows at 270 MPa (39.2 ksi) vs 250 MPa (36.3 ksi). In exchange, 355-T6 is the more ductile: elongation 3% versus 1% for 355-T7. 355-T7 runs hotter in service (200°C vs 175°C continuous) and 355-T7 conducts electricity better (42 % IACS vs 36 % IACS).
355-T6Choose it when the part is bent, formed or impact-loaded.
355-T7Choose it when strength drives the design, or when the part sees heat.
355-T6 vs 355-T7: 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
Fracture Toughness (K_IC)
Same in both: Elastic (Young's) Modulus 71 GPa10.3 Msi · Shear Modulus 26.5 GPa3.8 Msi · Bulk Modulus 69 GPa10 Msi · Poisson's Ratio 0.33 · Fatigue Strength (Endurance Limit) 62 MPa9 ksi · Hardness, Brinell 85 HB
Physical
Density and transition temperatures.
Same in both: Density 2.71 g/cm³0.1 lb/in³ · Melting Point (Solidus) 546°C1,015 °F · Liquidus Temperature 621°C1,150 °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) 22.4 µm/m·K12.4 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) -0.78 V
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Formability (cold)
Same in both: Machinability 62 / 100 · Machinability Rating (AISI 1212 = 100 %) 60% · Weldability 55 / 100 · Castability 85 / 100 · Brazeability / Solderability 25 / 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 kg CO₂/kg · Embodied Water 1,100 L/kg132 gal/lb · Typical Recycled Content 80%
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.
355-T6 vs 355-T7 — frequently asked
Is 355-T7 stronger than 355-T6?
Yes. 355-T7 has a typical yield strength of 250 MPa (36.3 ksi) against 180 MPa (26.1 ksi) for 355-T6 — about 39% more. Tensile strength is 270 MPa (39.2 ksi) vs 250 MPa (36.3 ksi).
Which condition does FabDigit quote by default, T6 or T7?
Specify the condition in the material field or the drawing note; FabDigit prices the quote for the state you call out.
When should I choose 355-T6 over 355-T7?
Pick 355-T6 when the part is bent, formed or impact-loaded. Pick 355-T7 when strength drives the design, or when the part sees heat.
Ready to make it?
Upload a CAD file and FabDigit prices the part in 355-T6 and 355-T7 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.