Aluminum 390-T6 vs 390-T7
Aluminum · 390 temper comparison
390-T6 and 390-T7 are two conditions of the same aluminum grade, 390: 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. 390-T6 is the stronger of the two: yield strength 310 MPa (45 ksi) against 262 MPa (38 ksi) for 390-T7, about 18% more; tensile strength follows at 310 MPa (45 ksi) vs 262 MPa (38 ksi). 390-T6 is harder — 145 HB against 120 HB for 390-T7 — which matters for wear surfaces and threads. 390-T7 runs hotter in service (200°C vs 175°C continuous) and 390-T7 conducts electricity better (28 % IACS vs 25 % IACS).
390-T6Choose it when strength drives the design, or when surface hardness matters.
390-T7Choose it when the part sees heat.
390-T6 vs 390-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)
Shear Strength
Fatigue Strength (Endurance Limit)
Hardness, Brinell
Same in both: Elastic (Young's) Modulus 81 GPa11.7 Msi · Shear Modulus 30.5 GPa4.4 Msi · Bulk Modulus 79 GPa11.5 Msi · Poisson's Ratio 0.33 · Elongation at Break 1% · Fracture Toughness (K_IC) 15 MPa·√m13.7 ksi·√in · Charpy V-Notch Impact (RT) 2 J1.5 ft·lbf
Physical
Density and transition temperatures.
Same in both: Density 2.73 g/cm³0.1 lb/in³ · Melting Point (Solidus) 507°C945 °F · Liquidus Temperature 649°C1,200 °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 880 J/kg·K0.21 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 18 µm/m·K10 µin/in·°F · Latent Heat of Fusion 480 J/g206 BTU/lb · Min Service Temperature -80°C-112 °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) -0.75 V
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability Rating (AISI 1212 = 100 %)
Weldability
Same in both: Machinability 32 / 100 · Formability (cold) 3 / 100 · Castability 82 / 100 · Brazeability / Solderability 20 / 100 · Polishability 40 / 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 70%
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.
390-T6 vs 390-T7 — frequently asked
Is 390-T6 stronger than 390-T7?
Yes. 390-T6 has a typical yield strength of 310 MPa (45 ksi) against 262 MPa (38 ksi) for 390-T7 — about 18% more. Tensile strength is 310 MPa (45 ksi) vs 262 MPa (38 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 390-T6 over 390-T7?
Pick 390-T6 when strength drives the design, or when surface hardness matters. Pick 390-T7 when the part sees heat.
Ready to make it?
Upload a CAD file and FabDigit prices the part in 390-T6 and 390-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.