Aluminum 355 vs A390
Aluminum · grade comparison
Aluminum 355 and A390 are both aluminum grades, both cast al. A390 is the stronger of the two: yield strength 240 MPa (34.8 ksi) against 180 MPa (26.1 ksi) for 355, about 33% more; tensile strength follows at 280 MPa (40.6 ksi) vs 250 MPa (36.3 ksi). In exchange, 355 is the more ductile: elongation 3% versus 1% for A390, and A390 is harder (120 HB vs 85 HB). A390 is stiffer (81 GPa vs 71 GPa) and A390 runs hotter in service (200°C vs 175°C continuous). On the shop floor, 355 machines more easily (good vs poor), 355 welds better (good vs poor), and 355 sits in a lower cost tier (budget, $) than A390 (standard, $$).
355Choose it when the part is bent, formed or impact-loaded, or when the part is machined in volume.
A390Choose it when strength drives the design, or when the part sees heat.
355 vs A390: 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.
Elastic (Young's) Modulus
Shear Modulus
Bulk Modulus
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
Hardness, Brinell
Compressive Strength
Charpy V-Notch Impact (RT)
Hardness, Vickers
Same in both: Poisson's Ratio 0.33 · Shear Strength 195 MPa28.3 ksi
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)
Latent Heat of Fusion
Max Service Temperature (continuous)
Same in both: Specific Heat Capacity 963 J/kg·K0.23 BTU/lb·°F · 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.
Machinability
Machinability Rating (AISI 1212 = 100 %)
Weldability
Formability (cold)
Castability
Brazeability / Solderability
Polishability
Sustainability
Primary-production footprint per kilogram.
Embodied Water
Typical Recycled Content
Same in both: Embodied Energy (primary production) 200 MJ/kg85,985 BTU/lb · 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 | A390 |
|---|---|---|
| Default condition | — | — |
| Relative cost | $ Budget | $$ Standard |
| 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 A390 — frequently asked
Is A390 stronger than 355?
Yes. A390 has a typical yield strength of 240 MPa (34.8 ksi) against 180 MPa (26.1 ksi) for 355 — about 33% more. Tensile strength is 280 MPa (40.6 ksi) vs 250 MPa (36.3 ksi).
Which is cheaper, 355 or A390?
355 is the lower-cost material: it sits in the budget tier ($) while A390 is standard ($$). Part price depends far more on geometry, tolerance and quantity than on raw stock — upload a CAD file for a live quote.
Which is easier to machine, 355 or A390?
355. Its machinability rates good (62/100) against poor (30/100) for A390; for welding the order is 355 first (good, 55/100) then A390 (poor, 20/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in 355 and A390 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.