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Aluminum 355 vs LM24

Aluminum · grade comparison

Aluminum 355 and LM24 are both aluminum grades, both cast al. 355 is the stronger of the two: yield strength 180 MPa (26.1 ksi) against 160 MPa (23.2 ksi) for LM24, about 13% more. 355 is the more ductile: elongation 3% versus 2% for LM24. 355 runs hotter in service (175°C vs 150°C continuous) and 355 conducts heat better (151 W/m·K vs 100 W/m·K). On the shop floor, LM24 machines more easily (very good vs good) and 355 welds better (good vs poor).

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

LM24Choose it when the part is machined in volume.

355 vs LM24: properties

355LM24

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Shear Modulus

26.5 GPa3.8 Msi
27 GPa3.9 Msi

Bulk Modulus

69 GPa10 Msi
70 GPa10.2 Msi

Tensile Strength (Ultimate)

250 MPa36.3 ksi
280 MPa40.6 ksi

Yield Strength (0.2% offset)

180 MPa26.1 ksi
160 MPa23.2 ksi

Elongation at Break

3%
2%

Shear Strength

195 MPa28.3 ksi
185 MPa26.8 ksi

Fatigue Strength (Endurance Limit)

62 MPa9 ksi
138 MPa20 ksi

Fracture Toughness (K_IC)

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

Compressive Strength

—
290 MPa42.1 ksi

Charpy V-Notch Impact (RT)

—
3 J2.2 ft·lbf

Hardness, Vickers

—
90 HV

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

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

Melting Point (Solidus)

546°C1,015 °F
520°C968 °F

Liquidus Temperature

621°C1,150 °F
590°C1,094 °F

Thermal

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

Thermal Conductivity

151 W/m·K87.2 BTU/hr·ft·°F
100 W/m·K57.8 BTU/hr·ft·°F

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

Min Service Temperature

-196°C-321 °F
-100°C-148 °F

Same in both: Specific Heat Capacity 963 J/kg·K0.23 BTU/lb·°F · Latent Heat of Fusion 389 J/g167 BTU/lb

Electrical

Conductivity and insulation.

Electrical Conductivity

36 % IACS
24 % IACS

Electrical Resistivity

4.8×10⁻⁸ Ω·m1.89 µΩ·in
7.2×10⁻⁸ Ω·m2.83 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

45 / 100
42 / 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
80 / 100

Machinability Rating (AISI 1212 = 100 %)

60%
—

Weldability

55 / 100
25 / 100

Castability

85 / 100
92 / 100

Brazeability / Solderability

25 / 100
20 / 100

Polishability

45 / 100
40 / 100

Same in both: Formability (cold) 5 / 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%
90%

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
100 kN·m/kg

Specific Stiffness (E / density)

26.2 MN·m/kg
25.4 MN·m/kg

Modulus of Resilience

228 kJ/m³
180 kJ/m³

Thermal Diffusivity

57.9 mm²/s
37.2 mm²/s

Thermal Shock Resistance Index

24
18

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 scale355LM24

Manufacturing and finishing

Capability355LM24
Default condition—F
Relative cost$ Budget$ Budget
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 LM24 — frequently asked

Is 355 stronger than LM24?

Yes. 355 has a typical yield strength of 180 MPa (26.1 ksi) against 160 MPa (23.2 ksi) for LM24 — about 13% more. Tensile strength is 250 MPa (36.3 ksi) vs 280 MPa (40.6 ksi).

Which is cheaper, 355 or LM24?

Both sit in the same relative cost tier ($, budget); the part price will be decided by machining time, tolerance and quantity rather than by the material.

Which is easier to machine, 355 or LM24?

LM24. Its machinability rates very good (80/100) against good (62/100) for 355; for welding the order is 355 first (good, 55/100) then LM24 (poor, 25/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in 355 and LM24 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.