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Aluminum 242.0 vs 355

Aluminum · grade comparison

Aluminum 242.0 and 355 are both aluminum grades. 242.0 is the stronger of the two: yield strength 207 MPa (30 ksi) against 180 MPa (26.1 ksi) for 355, about 15% more. In exchange, 355 is the more ductile: elongation 3% versus 0.5% for 242.0. 355 is lighter (2.71 g/cm³ vs 2.81 g/cm³ for 242.0) and 242.0 runs hotter in service (250°C vs 175°C continuous). On the shop floor, 242.0 machines more easily (very good vs good), 355 welds better (good vs poor), and 355 sits in a lower cost tier (budget, $) than 242.0 (standard, $$).

242.0Choose it when strength drives the design, or when the part sees heat.

355Choose it when the part is bent, formed or impact-loaded, or when weight is the constraint.

242.0 vs 355: properties

242.0355

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Shear Modulus

27 GPa3.9 Msi
26.5 GPa3.8 Msi

Bulk Modulus

71 GPa10.3 Msi
69 GPa10 Msi

Tensile Strength (Ultimate)

221 MPa32.1 ksi
250 MPa36.3 ksi

Yield Strength (0.2% offset)

207 MPa30 ksi
180 MPa26.1 ksi

Elongation at Break

0.5%
3%

Shear Strength

179 MPa26 ksi
195 MPa28.3 ksi

Fatigue Strength (Endurance Limit)

75 MPa10.9 ksi
62 MPa9 ksi

Fracture Toughness (K_IC)

17 MPa·√m15.5 ksi·√in
20 MPa·√m18.2 ksi·√in

Charpy V-Notch Impact (RT)

3 J1.8 ft·lbf
—

Same in both: Elastic (Young's) Modulus 71 GPa10.3 Msi · Poisson's Ratio 0.33 · Hardness, Brinell 85 HB

Physical

Density and transition temperatures.

Density

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

Melting Point (Solidus)

528°C982 °F
546°C1,015 °F

Liquidus Temperature

635°C1,175 °F
621°C1,150 °F

Thermal

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

Thermal Conductivity

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

Specific Heat Capacity

921 J/kg·K0.22 BTU/lb·°F
963 J/kg·K0.23 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

22.5 µm/m·K12.5 µin/in·°F
22.4 µm/m·K12.4 µin/in·°F

Max Service Temperature (continuous)

250°C482 °F
175°C347 °F

Same in both: Latent Heat of Fusion 389 J/g167 BTU/lb · Min Service Temperature -196°C-321 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

34 % IACS
36 % IACS

Electrical Resistivity

5.1×10⁻⁸ Ω·m2.01 µΩ·in
4.8×10⁻⁸ Ω·m1.89 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.72 V
-0.78 V

Corrosion Resistance

32 / 100
45 / 100

Manufacturability

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

Machinability

72 / 100
62 / 100

Weldability

22 / 100
55 / 100

Castability

48 / 100
85 / 100

Brazeability / Solderability

15 / 100
25 / 100

Machinability Rating (AISI 1212 = 100 %)

—
60%

Same in both: Formability (cold) 5 / 100 · Polishability 45 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

205 MJ/kg88,134 BTU/lb
200 MJ/kg85,985 BTU/lb

Embodied Carbon (primary production)

11.5 kg CO₂/kg
12 kg CO₂/kg

Embodied Water

1,150 L/kg138 gal/lb
1,100 L/kg132 gal/lb

Typical Recycled Content

45%
80%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

79 kN·m/kg
92 kN·m/kg

Specific Stiffness (E / density)

25.3 MN·m/kg
26.2 MN·m/kg

Modulus of Resilience

302 kJ/m³
228 kJ/m³

Thermal Diffusivity

50.2 mm²/s
57.9 mm²/s

Thermal Shock Resistance Index

18
24

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 scale355242.0

Manufacturing and finishing

Capability242.0355
CNC machining—Yes
Default condition——
Relative cost$$ Standard$ Budget
Min. machined wall—0.5 mm
Best machined surface—Ra 0.8 µm
Anodizing Type II—Yes
Cerakote—Yes
Chem Film (Alodine)—Yes
DLC—Yes
E-Coating—Yes
Electropolishing—Yes
Hard Anodize Type III w/ PTFE—Yes
Hard Anodizing Type III—Yes
Nickel Plating—Yes
PTFE Coating—Yes
Painting—Yes
Powder Coating—Yes

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

242.0 vs 355 — frequently asked

Is 242.0 stronger than 355?

Yes. 242.0 has a typical yield strength of 207 MPa (30 ksi) against 180 MPa (26.1 ksi) for 355 — about 15% more. Tensile strength is 221 MPa (32.1 ksi) vs 250 MPa (36.3 ksi).

Which is cheaper, 242.0 or 355?

355 is the lower-cost material: it sits in the budget tier ($) while 242.0 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, 242.0 or 355?

242.0. Its machinability rates very good (72/100) against good (62/100) for 355; for welding the order is 355 first (good, 55/100) then 242.0 (poor, 22/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in 242.0 and 355 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.