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Aluminum 355 vs A380

Aluminum · grade comparison

Aluminum 355 and A380 are both aluminum grades, both cast al. 355 is the stronger of the two: yield strength 180 MPa (26.1 ksi) against 159 MPa (23.1 ksi) for A380, about 13% more. In exchange, A380 is the more ductile: elongation 3.5% versus 3% for 355, and 355 is harder (85 HB vs 80 HB). 355 runs hotter in service (175°C vs 150°C continuous) 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 sees heat.

A380Choose it when the part is bent, formed or impact-loaded.

355 vs A380: properties

355A380

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Bulk Modulus

69 GPa10 Msi
72 GPa10.4 Msi

Tensile Strength (Ultimate)

250 MPa36.3 ksi
324 MPa47 ksi

Yield Strength (0.2% offset)

180 MPa26.1 ksi
159 MPa23.1 ksi

Elongation at Break

3%
3.5%

Shear Strength

195 MPa28.3 ksi
190 MPa27.6 ksi

Fatigue Strength (Endurance Limit)

62 MPa9 ksi
138 MPa20 ksi

Fracture Toughness (K_IC)

20 MPa·√m18.2 ksi·√in
18 MPa·√m16.4 ksi·√in

Hardness, Brinell

85 HB
80 HB

Charpy V-Notch Impact (RT)

—
3 J2.2 ft·lbf

Same in both: Elastic (Young's) Modulus 71 GPa10.3 Msi · Shear Modulus 26.5 GPa3.8 Msi · Poisson's Ratio 0.33

Physical

Density and transition temperatures.

Density

2.71 g/cm³0.1 lb/in³
2.76 g/cm³0.1 lb/in³

Melting Point (Solidus)

546°C1,015 °F
540°C1,004 °F

Liquidus Temperature

621°C1,150 °F
595°C1,103 °F

Thermal

How each material carries heat and how hot it can run.

Thermal Conductivity

151 W/m·K87.2 BTU/hr·ft·°F
96 W/m·K55.5 BTU/hr·ft·°F

Thermal Expansion (CTE, 20–100 °C)

22.4 µm/m·K12.4 µin/in·°F
21.8 µm/m·K12.1 µin/in·°F

Max Service Temperature (continuous)

175°C347 °F
150°C302 °F

Min Service Temperature

-196°C-321 °F
-80°C-112 °F

Same in both: Specific Heat Capacity 963 J/kg·K0.23 BTU/lb·°F · Latent Heat of Fusion 389 J/g167 BTU/lb

Electrical

Conductivity and insulation.

Electrical Conductivity

36 % IACS
23 % IACS

Electrical Resistivity

4.8×10⁻⁸ Ω·m1.89 µΩ·in
7.5×10⁻⁸ Ω·m2.95 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.78 V
-0.76 V

Corrosion Resistance

45 / 100
42 / 100

Manufacturability

FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.

Machinability

62 / 100
70 / 100

Machinability Rating (AISI 1212 = 100 %)

60%
—

Weldability

55 / 100
25 / 100

Formability (cold)

5 / 100
10 / 100

Castability

85 / 100
92 / 100

Brazeability / Solderability

25 / 100
30 / 100

Same in both: Polishability 45 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

200 MJ/kg85,985 BTU/lb
195 MJ/kg83,835 BTU/lb

Embodied Carbon (primary production)

12 kg CO₂/kg
11.5 kg CO₂/kg

Typical Recycled Content

80%
85%

Same in both: Embodied Water 1,100 L/kg132 gal/lb

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

92 kN·m/kg
117 kN·m/kg

Specific Stiffness (E / density)

26.2 MN·m/kg
25.7 MN·m/kg

Modulus of Resilience

228 kJ/m³
178 kJ/m³

Thermal Diffusivity

57.9 mm²/s
36.1 mm²/s

Thermal Shock Resistance Index

24
20

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.

20501002005002.22.42.62.83Density (g/cm³)Yield strength (MPa) — log scale355A380

Manufacturing and finishing

Capability355A380
Casting & forging—Yes
Default condition——
Relative cost$ Budget$ Budget
Min. machined wall0.5 mm1 mm
Best machined surfaceRa 0.8 µmRa 1.6 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 A380 — frequently asked

Is 355 stronger than A380?

Yes. 355 has a typical yield strength of 180 MPa (26.1 ksi) against 159 MPa (23.1 ksi) for A380 — about 13% more. Tensile strength is 250 MPa (36.3 ksi) vs 324 MPa (47 ksi).

Which is cheaper, 355 or A380?

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 is easier to machine, 355 or A380?

A380. Its machinability rates very good (70/100) against good (62/100) for 355; for welding the order is 355 first (good, 55/100) then A380 (poor, 25/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in 355 and A380 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.