Aluminum 2618A-T4 vs 2618A-T651
Aluminum · 2618A temper comparison
2618A-T4 and 2618A-T651 are two conditions of the same aluminum grade, 2618A: T4 (solution heat treated and naturally aged) versus T651 (T6, stress relieved by stretching). The chemistry is identical, so every difference below comes from the condition. 2618A-T651 is the stronger of the two: yield strength 378 MPa (54.8 ksi) against 240 MPa (34.8 ksi) for 2618A-T4, about 57% more; tensile strength follows at 440 MPa (63.8 ksi) vs 380 MPa (55.1 ksi). In exchange, 2618A-T4 is the more ductile: elongation 16% versus 8% for 2618A-T651, and 2618A-T651 is harder (118 HB vs 95 HB). 2618A-T651 runs hotter in service (200°C vs 100°C continuous) and 2618A-T651 conducts heat better (146 W/m·K vs 130 W/m·K).
2618A-T4Choose it when the part is bent, formed or impact-loaded.
2618A-T651Choose it when strength drives the design, or when the part sees heat.
2618A-T4 vs 2618A-T651: 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
Reduction in Area
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 74 GPa10.7 Msi · Shear Modulus 27.5 GPa4 Msi · Bulk Modulus 72 GPa10.4 Msi · Poisson's Ratio 0.33
Physical
Density and transition temperatures.
Same in both: Density 2.76 g/cm³0.1 lb/in³ · Melting Point (Solidus) 502°C936 °F · Liquidus Temperature 638°C1,180 °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 875 J/kg·K0.21 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 22.3 µm/m·K12.4 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) -0.72 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 18 / 100 · Brazeability / Solderability 15 / 100 · Polishability 45 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 210 MJ/kg90,284 BTU/lb · Embodied Carbon (primary production) 14 kg CO₂/kg · Embodied Water 1,200 L/kg144 gal/lb · Typical Recycled Content 12%
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.
2618A-T4 vs 2618A-T651 — frequently asked
Is 2618A-T651 stronger than 2618A-T4?
Yes. 2618A-T651 has a typical yield strength of 378 MPa (54.8 ksi) against 240 MPa (34.8 ksi) for 2618A-T4 — about 57% more. Tensile strength is 440 MPa (63.8 ksi) vs 380 MPa (55.1 ksi).
Which condition does FabDigit quote by default, T4 or T651?
T851 is the default 2618A condition in the FabDigit quote flow (neither T4 nor T651). 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 is easier to machine, 2618A-T4 or 2618A-T651?
2618A-T651. Its machinability rates very good (70/100) against good (62/100) for 2618A-T4.
Ready to make it?
Upload a CAD file and FabDigit prices the part in 2618A-T4 and 2618A-T651 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.