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Aluminum 356 vs LM25

Aluminum · grade comparison

Aluminum 356 and LM25 are both aluminum grades, both cast al. LM25 is the stronger of the two: yield strength 215 MPa (31.2 ksi) against 186 MPa (27 ksi) for 356, about 16% more. In exchange, 356 is the more ductile: elongation 5% versus 3% for LM25, and LM25 is harder (95 HB vs 80 HB). On the shop floor, 356 sits in a lower cost tier (budget, $) than LM25 (standard, $$).

356Choose it when the part is bent, formed or impact-loaded, or when cost is the deciding factor.

LM25Choose it when strength drives the design.

356 vs LM25: properties

356LM25

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

72.4 GPa10.5 Msi
71 GPa10.3 Msi

Shear Modulus

27 GPa3.9 Msi
26.5 GPa3.8 Msi

Bulk Modulus

71 GPa10.3 Msi
70 GPa10.2 Msi

Tensile Strength (Ultimate)

262 MPa38 ksi
250 MPa36.3 ksi

Yield Strength (0.2% offset)

186 MPa27 ksi
215 MPa31.2 ksi

Elongation at Break

5%
3%

Compressive Strength

190 MPa27.6 ksi
—

Shear Strength

179 MPa26 ksi
180 MPa26.1 ksi

Fracture Toughness (K_IC)

20 MPa·√m18.2 ksi·√in
22 MPa·√m20 ksi·√in

Charpy V-Notch Impact (RT)

5 J3.7 ft·lbf
4 J3 ft·lbf

Hardness, Brinell

80 HB
95 HB

Hardness, Vickers

—
100 HV

Same in both: Poisson's Ratio 0.33 · Fatigue Strength (Endurance Limit) 90 MPa13.1 ksi

Physical

Density and transition temperatures.

Density

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

Melting Point (Solidus)

557°C1,035 °F
555°C1,031 °F

Liquidus Temperature

613°C1,135 °F
615°C1,139 °F

Thermal

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

Thermal Expansion (CTE, 20–100 °C)

21.5 µm/m·K11.9 µin/in·°F
22 µm/m·K12.2 µin/in·°F

Same in both: Thermal Conductivity 151 W/m·K87.2 BTU/hr·ft·°F · Specific Heat Capacity 963 J/kg·K0.23 BTU/lb·°F · Latent Heat of Fusion 389 J/g167 BTU/lb · Max Service Temperature (continuous) 150°C302 °F · Min Service Temperature -196°C-321 °F

Electrical

Conductivity and insulation.

Same in both: Electrical Conductivity 39 % IACS · Electrical Resistivity 4.4×10⁻⁸ Ω·m1.73 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

62 / 100
65 / 100

Same in both: Galvanic Potential (seawater, vs SCE) -0.83 V

Manufacturability

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

Machinability

70 / 100
65 / 100

Machinability Rating (AISI 1212 = 100 %)

120%
70%

Weldability

78 / 100
75 / 100

Brazeability / Solderability

30 / 100
35 / 100

Same in both: Formability (cold) 10 / 100 · Castability 95 / 100 · Polishability 45 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

200 MJ/kg85,985 BTU/lb
190 MJ/kg81,685 BTU/lb

Embodied Carbon (primary production)

12.5 kg CO₂/kg
12 kg CO₂/kg

Typical Recycled Content

60%
50%

Same in both: Embodied Water 1,200 L/kg144 gal/lb

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

98 kN·m/kg
93 kN·m/kg

Specific Stiffness (E / density)

27.1 MN·m/kg
26.5 MN·m/kg

Modulus of Resilience

239 kJ/m³
326 kJ/m³

Thermal Diffusivity

58.7 mm²/s
58.5 mm²/s

Thermal Shock Resistance Index

25
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 scale356LM25

Manufacturing and finishing

Capability356LM25
Default condition—T6
Relative cost$ Budget$$ Standard
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.

356 vs LM25 — frequently asked

Is LM25 stronger than 356?

Yes. LM25 has a typical yield strength of 215 MPa (31.2 ksi) against 186 MPa (27 ksi) for 356 — about 16% more. Tensile strength is 250 MPa (36.3 ksi) vs 262 MPa (38 ksi).

Which is cheaper, 356 or LM25?

356 is the lower-cost material: it sits in the budget tier ($) while LM25 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 LM25?

356. Its machinability rates very good (70/100) against good (65/100) for LM25.

Ready to make it?

Upload a CAD file and FabDigit prices the part in 356 and LM25 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.