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Aluminum 356 vs AL25

Aluminum · grade comparison

Aluminum 356 and AL25 are both aluminum grades. 356 is the stronger of the two: tensile strength 262 MPa (38 ksi) against 200 MPa (29 ksi) for AL25, about 31% more. 356 is the more ductile: elongation 5% versus 0.6% for AL25, and AL25 is harder (95 HB vs 80 HB). AL25 is stiffer (80 GPa vs 72.4 GPa) and AL25 runs hotter in service (250°C vs 150°C continuous). On the shop floor, 356 machines more easily (very good vs fair), 356 welds better (very good vs poor), and 356 sits in a lower cost tier (budget, $) than AL25 (standard, $$).

356Choose it when strength drives the design, or when the part is bent, formed or impact-loaded.

AL25Choose it when the part sees heat.

356 vs AL25: properties

356AL25

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

72.4 GPa10.5 Msi
80 GPa11.6 Msi

Shear Modulus

27 GPa3.9 Msi
30 GPa4.4 Msi

Bulk Modulus

71 GPa10.3 Msi
73 GPa10.6 Msi

Tensile Strength (Ultimate)

262 MPa38 ksi
200 MPa29 ksi

Yield Strength (0.2% offset)

186 MPa27 ksi
180 MPa26.1 ksi

Elongation at Break

5%
0.6%

Compressive Strength

190 MPa27.6 ksi
—

Shear Strength

179 MPa26 ksi
145 MPa21 ksi

Fatigue Strength (Endurance Limit)

90 MPa13.1 ksi
70 MPa10.2 ksi

Fracture Toughness (K_IC)

20 MPa·√m18.2 ksi·√in
16 MPa·√m14.6 ksi·√in

Charpy V-Notch Impact (RT)

5 J3.7 ft·lbf
3 J1.8 ft·lbf

Hardness, Brinell

80 HB
95 HB

Hardness, Rockwell B

—
55 HRB

Hardness, Vickers

—
100 HV

Same in both: Poisson's Ratio 0.33

Physical

Density and transition temperatures.

Density

2.67 g/cm³0.1 lb/in³
2.73 g/cm³0.1 lb/in³

Melting Point (Solidus)

557°C1,035 °F
510°C950 °F

Liquidus Temperature

613°C1,135 °F
585°C1,085 °F

Thermal

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

Thermal Conductivity

151 W/m·K87.2 BTU/hr·ft·°F
130 W/m·K75.1 BTU/hr·ft·°F

Specific Heat Capacity

963 J/kg·K0.23 BTU/lb·°F
880 J/kg·K0.21 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

21.5 µm/m·K11.9 µin/in·°F
19 µm/m·K10.6 µin/in·°F

Latent Heat of Fusion

389 J/g167 BTU/lb
470 J/g202 BTU/lb

Max Service Temperature (continuous)

150°C302 °F
250°C482 °F

Min Service Temperature

-196°C-321 °F
-50°C-58 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

39 % IACS
27 % IACS

Electrical Resistivity

4.4×10⁻⁸ Ω·m1.73 µΩ·in
6.4×10⁻⁸ Ω·m2.52 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.83 V
-0.78 V

Corrosion Resistance

62 / 100
35 / 100

Manufacturability

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

Machinability

70 / 100
48 / 100

Machinability Rating (AISI 1212 = 100 %)

120%
55%

Weldability

78 / 100
25 / 100

Formability (cold)

10 / 100
5 / 100

Castability

95 / 100
85 / 100

Brazeability / Solderability

30 / 100
20 / 100

Polishability

45 / 100
40 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Carbon (primary production)

12.5 kg CO₂/kg
12 kg CO₂/kg

Same in both: Embodied Energy (primary production) 200 MJ/kg85,985 BTU/lb · Embodied Water 1,200 L/kg144 gal/lb · Typical Recycled Content 60%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

98 kN·m/kg
73 kN·m/kg

Specific Stiffness (E / density)

27.1 MN·m/kg
29.3 MN·m/kg

Modulus of Resilience

239 kJ/m³
203 kJ/m³

Thermal Diffusivity

58.7 mm²/s
54.1 mm²/s

Thermal Shock Resistance Index

25
17

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 scale356AL25

Manufacturing and finishing

Capability356AL25
CNC machiningYes—
Default condition——
Relative cost$ Budget$$ Standard
Min. machined wall0.5 mm—
Best machined surfaceRa 0.8 µm—
Anodizing Type IIYes—
CerakoteYes—
Chem Film (Alodine)Yes—
DLCYes—
E-CoatingYes—
ElectropolishingYes—
Hard Anodize Type III w/ PTFEYes—
Hard Anodizing Type IIIYes—
Nickel PlatingYes—
PTFE CoatingYes—
PaintingYes—
Powder CoatingYes—

They share 4 finishes: Electroless Nickel (EN), Epoxy Coating, Gold Plating, Silver Plating.

356 vs AL25 — frequently asked

Is 356 stronger than AL25?

Yes. 356 has a typical tensile strength of 262 MPa (38 ksi) against 200 MPa (29 ksi) for AL25 — about 31% more.

Which is cheaper, 356 or AL25?

356 is the lower-cost material: it sits in the budget tier ($) while AL25 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, 356 or AL25?

356. Its machinability rates very good (70/100) against fair (48/100) for AL25; for welding the order is 356 first (very good, 78/100) then AL25 (poor, 25/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in 356 and AL25 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.