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Aluminum 355 vs AL25

Aluminum · grade comparison

Aluminum 355 and AL25 are both aluminum grades. 355 is the stronger of the two: tensile strength 250 MPa (36.3 ksi) against 200 MPa (29 ksi) for AL25, about 25% more. 355 is the more ductile: elongation 3% versus 0.6% for AL25, and AL25 is harder (95 HB vs 85 HB). AL25 is stiffer (80 GPa vs 71 GPa) and AL25 runs hotter in service (250°C vs 175°C continuous). On the shop floor, 355 machines more easily (good vs fair), 355 welds better (good vs poor), and 355 sits in a lower cost tier (budget, $) than AL25 (standard, $$).

355Choose it when strength drives the design, or when the part is bent, formed or impact-loaded.

AL25Choose it when the part sees heat.

355 vs AL25: properties

355AL25

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

71 GPa10.3 Msi
80 GPa11.6 Msi

Shear Modulus

26.5 GPa3.8 Msi
30 GPa4.4 Msi

Bulk Modulus

69 GPa10 Msi
73 GPa10.6 Msi

Tensile Strength (Ultimate)

250 MPa36.3 ksi
200 MPa29 ksi

Elongation at Break

3%
0.6%

Shear Strength

195 MPa28.3 ksi
145 MPa21 ksi

Fatigue Strength (Endurance Limit)

62 MPa9 ksi
70 MPa10.2 ksi

Fracture Toughness (K_IC)

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

Hardness, Brinell

85 HB
95 HB

Charpy V-Notch Impact (RT)

—
3 J1.8 ft·lbf

Hardness, Rockwell B

—
55 HRB

Hardness, Vickers

—
100 HV

Same in both: Poisson's Ratio 0.33 · Yield Strength (0.2% offset) 180 MPa26.1 ksi

Physical

Density and transition temperatures.

Density

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

Melting Point (Solidus)

546°C1,015 °F
510°C950 °F

Liquidus Temperature

621°C1,150 °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)

22.4 µm/m·K12.4 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)

175°C347 °F
250°C482 °F

Min Service Temperature

-196°C-321 °F
-50°C-58 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

36 % IACS
27 % IACS

Electrical Resistivity

4.8×10⁻⁸ Ω·m1.89 µΩ·in
6.4×10⁻⁸ Ω·m2.52 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

45 / 100
35 / 100

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

62 / 100
48 / 100

Machinability Rating (AISI 1212 = 100 %)

60%
55%

Weldability

55 / 100
25 / 100

Brazeability / Solderability

25 / 100
20 / 100

Polishability

45 / 100
40 / 100

Same in both: Formability (cold) 5 / 100 · Castability 85 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Water

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

Typical Recycled Content

80%
60%

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)

92 kN·m/kg
73 kN·m/kg

Specific Stiffness (E / density)

26.2 MN·m/kg
29.3 MN·m/kg

Modulus of Resilience

228 kJ/m³
203 kJ/m³

Thermal Diffusivity

57.9 mm²/s
54.1 mm²/s

Thermal Shock Resistance Index

24
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 scale355AL25

Manufacturing and finishing

Capability355AL25
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.

355 vs AL25 — frequently asked

Is 355 stronger than AL25?

Yes. 355 has a typical tensile strength of 250 MPa (36.3 ksi) against 200 MPa (29 ksi) for AL25 — about 25% more.

Which is cheaper, 355 or AL25?

355 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, 355 or AL25?

355. Its machinability rates good (62/100) against fair (48/100) for AL25; for welding the order is 355 first (good, 55/100) then AL25 (poor, 25/100).

Ready to make it?

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