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Aluminum 355 vs ZL401

Aluminum · grade comparison

Aluminum 355 and ZL401 are both aluminum grades. 355 is the stronger of the two: tensile strength 250 MPa (36.3 ksi) against 220 MPa (31.9 ksi) for ZL401, about 14% more. 355 is the more ductile: elongation 3% versus 2% for ZL401. 355 is lighter (2.71 g/cm³ vs 2.95 g/cm³ for ZL401) and 355 runs hotter in service (175°C vs 150°C continuous). On the shop floor, 355 welds better (good vs poor) and 355 sits in a lower cost tier (budget, $) than ZL401 (standard, $$).

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

355 vs ZL401: properties

355ZL401

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

71 GPa10.3 Msi
70 GPa10.2 Msi

Shear Modulus

26.5 GPa3.8 Msi
26 GPa3.8 Msi

Bulk Modulus

69 GPa10 Msi
70 GPa10.2 Msi

Tensile Strength (Ultimate)

250 MPa36.3 ksi
220 MPa31.9 ksi

Yield Strength (0.2% offset)

180 MPa26.1 ksi
175 MPa25.4 ksi

Elongation at Break

3%
2%

Shear Strength

195 MPa28.3 ksi
150 MPa21.8 ksi

Fatigue Strength (Endurance Limit)

62 MPa9 ksi
70 MPa10.2 ksi

Fracture Toughness (K_IC)

20 MPa·√m18.2 ksi·√in
15 MPa·√m13.7 ksi·√in

Reduction in Area

—
3%

Compressive Strength

—
230 MPa33.4 ksi

Charpy V-Notch Impact (RT)

—
4 J3 ft·lbf

Hardness, Rockwell B

—
52 HRB

Hardness, Vickers

—
89 HV

Same in both: Poisson's Ratio 0.33 · Hardness, Brinell 85 HB

Physical

Density and transition temperatures.

Density

2.71 g/cm³0.1 lb/in³
2.95 g/cm³0.11 lb/in³

Melting Point (Solidus)

546°C1,015 °F
545°C1,013 °F

Liquidus Temperature

621°C1,150 °F
610°C1,130 °F

Thermal

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

Thermal Conductivity

151 W/m·K87.2 BTU/hr·ft·°F
125 W/m·K72.2 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
24 µm/m·K13.3 µin/in·°F

Latent Heat of Fusion

389 J/g167 BTU/lb
380 J/g163 BTU/lb

Max Service Temperature (continuous)

175°C347 °F
150°C302 °F

Min Service Temperature

-196°C-321 °F
-50°C-58 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

36 % IACS
33 % IACS

Electrical Resistivity

4.8×10⁻⁸ Ω·m1.89 µΩ·in
5.2×10⁻⁸ Ω·m2.05 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.78 V
-0.9 V

Corrosion Resistance

45 / 100
43 / 100

Manufacturability

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

Machinability

62 / 100
55 / 100

Machinability Rating (AISI 1212 = 100 %)

60%
72%

Weldability

55 / 100
30 / 100

Formability (cold)

5 / 100
8 / 100

Castability

85 / 100
75 / 100

Polishability

45 / 100
40 / 100

Same in both: Brazeability / Solderability 25 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

200 MJ/kg85,985 BTU/lb
155 MJ/kg66,638 BTU/lb

Embodied Carbon (primary production)

12 kg CO₂/kg
9 kg CO₂/kg

Embodied Water

1,100 L/kg132 gal/lb
900 L/kg108 gal/lb

Typical Recycled Content

80%
60%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

92 kN·m/kg
75 kN·m/kg

Specific Stiffness (E / density)

26.2 MN·m/kg
23.7 MN·m/kg

Modulus of Resilience

228 kJ/m³
219 kJ/m³

Thermal Diffusivity

57.9 mm²/s
48.2 mm²/s

Thermal Shock Resistance Index

24
16

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 scale355ZL401

Manufacturing and finishing

Capability355ZL401
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 ZL401 — frequently asked

Is 355 stronger than ZL401?

Yes. 355 has a typical tensile strength of 250 MPa (36.3 ksi) against 220 MPa (31.9 ksi) for ZL401 — about 14% more.

Which is cheaper, 355 or ZL401?

355 is the lower-cost material: it sits in the budget tier ($) while ZL401 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 ZL401?

355, by a small margin. Both rate good for machinability — 62/100 against 55/100 for ZL401; for welding the order is 355 first (good, 55/100) then ZL401 (poor, 30/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in 355 and ZL401 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.