Aluminum 204.0-T4 vs 204.0-T6
Aluminum · 204.0 temper comparison
204.0-T4 and 204.0-T6 are two conditions of the same aluminum grade, 204.0: T4 (solution heat treated and naturally aged) versus T6 (solution heat treated and artificially aged). The chemistry is identical, so every difference below comes from the condition. 204.0-T6 is the stronger of the two: yield strength 285 MPa (41.3 ksi) against 195 MPa (28.3 ksi) for 204.0-T4, about 46% more; tensile strength follows at 350 MPa (50.8 ksi) vs 320 MPa (46.4 ksi). In exchange, 204.0-T4 is the more ductile: elongation 8% versus 3% for 204.0-T6, and 204.0-T6 is harder (120 HB vs 95 HB). 204.0-T6 runs hotter in service (175°C vs 150°C continuous) and 204.0-T6 conducts electricity better (37 % IACS vs 33 % IACS).
204.0-T4Choose it when the part is bent, formed or impact-loaded.
204.0-T6Choose it when strength drives the design, or when the part sees heat.
204.0-T4 vs 204.0-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
Shear Strength
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
Hardness, Brinell
Same in both: Elastic (Young's) Modulus 72 GPa10.4 Msi · Shear Modulus 27 GPa3.9 Msi · Bulk Modulus 71 GPa10.3 Msi · Poisson's Ratio 0.33 · Compressive Strength 200 MPa29 ksi
Physical
Density and transition temperatures.
Same in both: Density 2.8 g/cm³0.1 lb/in³ · Melting Point (Solidus) 571°C1,060 °F · Liquidus Temperature 650°C1,202 °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 900 J/kg·K0.21 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 22.7 µm/m·K12.6 µin/in·°F · Latent Heat of Fusion 390 J/g168 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) -0.7 V
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Machinability Rating (AISI 1212 = 100 %)
Weldability
Same in both: Formability (cold) 10 / 100 · Castability 35 / 100 · Brazeability / Solderability 20 / 100 · Polishability 60 / 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 15%
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.
204.0-T4 vs 204.0-T6 — frequently asked
Is 204.0-T6 stronger than 204.0-T4?
Yes. 204.0-T6 has a typical yield strength of 285 MPa (41.3 ksi) against 195 MPa (28.3 ksi) for 204.0-T4 — about 46% more. Tensile strength is 350 MPa (50.8 ksi) vs 320 MPa (46.4 ksi).
Which condition does FabDigit quote by default, T4 or T6?
T4 is the default 204.0 condition in the FabDigit quote flow. The other condition is available on request or by drawing note — specify it in the material field or the part notes and the quote is priced for it.
Which welds better, 204.0-T4 or 204.0-T6?
204.0-T4. Its weldability rates poor (25/100) against poor (20/100) for 204.0-T6.
Ready to make it?
Upload a CAD file and FabDigit prices the part in 204.0-T4 and 204.0-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.