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Aluminum 355 vs A356.2

Aluminum · grade comparison

Aluminum 355 and A356.2 are both aluminum grades. Both yield at about 180 MPa — strength does not separate them. A356.2 is the more ductile: elongation 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 A356.2 conducts electricity better (40 % IACS vs 36 % IACS). On the shop floor, A356.2 welds better (very good vs good) and 355 sits in a lower cost tier (budget, $) than A356.2 (premium, $$$).

355Choose it when the part sees heat, or when cost is the deciding factor.

A356.2Choose it when the part is bent, formed or impact-loaded, or when it will be welded.

355 vs A356.2: properties

355A356.2

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

71 GPa10.3 Msi
72.4 GPa10.5 Msi

Shear Modulus

26.5 GPa3.8 Msi
27 GPa3.9 Msi

Bulk Modulus

69 GPa10 Msi
71 GPa10.3 Msi

Tensile Strength (Ultimate)

250 MPa36.3 ksi
262 MPa38 ksi

Yield Strength (0.2% offset)

180 MPa26.1 ksi
186 MPa27 ksi

Elongation at Break

3%
5%

Shear Strength

195 MPa28.3 ksi
180 MPa26.1 ksi

Fatigue Strength (Endurance Limit)

62 MPa9 ksi
90 MPa13.1 ksi

Fracture Toughness (K_IC)

20 MPa·√m18.2 ksi·√in
22 MPa·√m20 ksi·√in

Hardness, Brinell

85 HB
80 HB

Compressive Strength

—
190 MPa27.6 ksi

Same in both: Poisson's Ratio 0.33

Physical

Density and transition temperatures.

Density

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

Melting Point (Solidus)

546°C1,015 °F
557°C1,035 °F

Liquidus Temperature

621°C1,150 °F
613°C1,135 °F

Thermal

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

Thermal Expansion (CTE, 20–100 °C)

22.4 µm/m·K12.4 µin/in·°F
21.5 µm/m·K11.9 µin/in·°F

Max Service Temperature (continuous)

175°C347 °F
150°C302 °F

Same in both: Thermal Conductivity 151 W/m·K87.2 BTU/hr·ft·°F · Specific Heat Capacity 963 J/kg·K0.23 BTU/lb·°F · Latent Heat of Fusion 389 J/g167 BTU/lb · Min Service Temperature -196°C-321 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

36 % IACS
40 % IACS

Electrical Resistivity

4.8×10⁻⁸ Ω·m1.89 µΩ·in
4.3×10⁻⁸ Ω·m1.69 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.78 V
-0.83 V

Corrosion Resistance

45 / 100
65 / 100

Manufacturability

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

Machinability Rating (AISI 1212 = 100 %)

60%
150%

Weldability

55 / 100
80 / 100

Formability (cold)

5 / 100
10 / 100

Castability

85 / 100
95 / 100

Brazeability / Solderability

25 / 100
40 / 100

Polishability

45 / 100
55 / 100

Same in both: Machinability 62 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

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

Embodied Water

1,100 L/kg132 gal/lb
1,200 L/kg144 gal/lb

Typical Recycled Content

80%
10%

Same in both: Embodied Carbon (primary production) 12 kg CO₂/kg

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

92 kN·m/kg
98 kN·m/kg

Specific Stiffness (E / density)

26.2 MN·m/kg
27 MN·m/kg

Modulus of Resilience

228 kJ/m³
239 kJ/m³

Thermal Diffusivity

57.9 mm²/s
58.5 mm²/s

Thermal Shock Resistance Index

24
25

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 scale355A356.2

Manufacturing and finishing

Capability355A356.2
Default condition—T6
Relative cost$ Budget$$$ Premium
Min. machined wall0.5 mm0.5 mm
Best machined surfaceRa 0.8 µmRa 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 A356.2 — frequently asked

What is the difference between 355 and A356.2?

Aluminum 355 and A356.2 are both aluminum grades. Both yield at about 180 MPa — strength does not separate them. A356.2 is the more ductile: elongation 5% versus 3% for 355, and 355 is harder (85 HB vs 80 HB).

Which is cheaper, 355 or A356.2?

355 is the lower-cost material: it sits in the budget tier ($) while A356.2 is premium ($$$). Part price depends far more on geometry, tolerance and quantity than on raw stock — upload a CAD file for a live quote.

Which welds better, 355 or A356.2?

A356.2. Its weldability rates very good (80/100) against good (55/100) for 355.

Ready to make it?

Upload a CAD file and FabDigit prices the part in 355 and A356.2 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.