Aluminum 355 vs 384
Aluminum · grade comparison
Aluminum 355 and 384 are both aluminum grades, both cast al. 355 is the stronger of the two: yield strength 180 MPa (26.1 ksi) against 165 MPa (23.9 ksi) for 384, about 9% more. 355 is the more ductile: elongation 3% versus 2.5% for 384. 355 is lighter (2.71 g/cm³ vs 2.82 g/cm³ for 384) and 355 conducts heat better (151 W/m·K vs 96 W/m·K). On the shop floor, 355 welds better (good vs poor).
355Choose it when strength drives the design, or when the part is bent, formed or impact-loaded.
355 vs 384: 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.
Bulk Modulus
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Shear Strength
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
Compressive Strength
Charpy V-Notch Impact (RT)
Same in both: Elastic (Young's) Modulus 71 GPa10.3 Msi · Shear Modulus 26.5 GPa3.8 Msi · Poisson's Ratio 0.33 · Hardness, Brinell 85 HB
Physical
Density and transition temperatures.
Density
Melting Point (Solidus)
Liquidus Temperature
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Thermal Expansion (CTE, 20–100 °C)
Min Service Temperature
Same in both: Specific Heat Capacity 963 J/kg·K0.23 BTU/lb·°F · Latent Heat of Fusion 389 J/g167 BTU/lb · Max Service Temperature (continuous) 175°C347 °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.
Machinability
Machinability Rating (AISI 1212 = 100 %)
Weldability
Castability
Brazeability / Solderability
Polishability
Same in both: Formability (cold) 5 / 100
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Water
Typical Recycled Content
Same in both: Embodied Carbon (primary production) 12 kg CO₂/kg
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Specific Stiffness (E / density)
Modulus of Resilience
Thermal Diffusivity
Thermal Shock Resistance Index
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.
Manufacturing and finishing
| Capability | 355 | 384 |
|---|---|---|
| Default condition | — | — |
| Relative cost | $ Budget | $ Budget |
| Min. machined wall | 0.5 mm | 0.5 mm |
| Best machined surface | Ra 0.8 µm | Ra 0.8 µm |
Both are offered for CNC machining. Both take the same 16 finishes: Anodizing Type II, Cerakote, Chem Film (Alodine), DLC, E-Coating, Electroless Nickel (EN), Electropolishing, Epoxy Coating, Gold Plating, Hard Anodize Type III w/ PTFE, Hard Anodizing Type III, Nickel Plating and 4 more.
355 vs 384 — frequently asked
Is 355 stronger than 384?
Yes. 355 has a typical yield strength of 180 MPa (26.1 ksi) against 165 MPa (23.9 ksi) for 384 — about 9% more. Tensile strength is 250 MPa (36.3 ksi) vs 330 MPa (47.9 ksi).
Which is cheaper, 355 or 384?
Both sit in the same relative cost tier ($, budget); the part price will be decided by machining time, tolerance and quantity rather than by the material.
Which welds better, 355 or 384?
355. Its weldability rates good (55/100) against poor (25/100) for 384.
Ready to make it?
Upload a CAD file and FabDigit prices the part in 355 and 384 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.