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Aluminum 356 vs LM6

Aluminum · grade comparison

Aluminum 356 and LM6 are both aluminum grades, both cast al. 356 is the stronger of the two: yield strength 186 MPa (27 ksi) against 70 MPa (10.2 ksi) for LM6, about 166% more; tensile strength follows at 262 MPa (38 ksi) vs 170 MPa (24.7 ksi). In exchange, LM6 is the more ductile: elongation 6% versus 5% for 356, and 356 is harder (80 HB vs 52 HB). 356 conducts heat better (151 W/m·K vs 130 W/m·K). On the shop floor, 356 machines more easily (very good vs fair).

356Choose it when strength drives the design, or when the part is machined in volume.

LM6Choose it when the part is bent, formed or impact-loaded.

356 vs LM6: properties

356LM6

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
170 MPa24.7 ksi

Yield Strength (0.2% offset)

186 MPa27 ksi
70 MPa10.2 ksi

Elongation at Break

5%
6%

Compressive Strength

190 MPa27.6 ksi
—

Shear Strength

179 MPa26 ksi
125 MPa18.1 ksi

Fatigue Strength (Endurance Limit)

90 MPa13.1 ksi
60 MPa8.7 ksi

Fracture Toughness (K_IC)

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

Charpy V-Notch Impact (RT)

5 J3.7 ft·lbf
3 J2.2 ft·lbf

Hardness, Brinell

80 HB
52 HB

Hardness, Vickers

—
57 HV

Same in both: Poisson's Ratio 0.33

Physical

Density and transition temperatures.

Density

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

Melting Point (Solidus)

557°C1,035 °F
574°C1,065 °F

Liquidus Temperature

613°C1,135 °F
582°C1,080 °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

Thermal Expansion (CTE, 20–100 °C)

21.5 µm/m·K11.9 µin/in·°F
20.4 µm/m·K11.3 µin/in·°F

Same in both: 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.

Electrical Conductivity

39 % IACS
33 % IACS

Electrical Resistivity

4.4×10⁻⁸ Ω·m1.73 µΩ·in
5.2×10⁻⁸ Ω·m2.05 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Same in both: Galvanic Potential (seawater, vs SCE) -0.83 V · Corrosion Resistance 62 / 100

Manufacturability

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

Machinability

70 / 100
40 / 100

Machinability Rating (AISI 1212 = 100 %)

120%
35%

Weldability

78 / 100
80 / 100

Formability (cold)

10 / 100
5 / 100

Brazeability / Solderability

30 / 100
35 / 100

Polishability

45 / 100
35 / 100

Same in both: Castability 95 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Carbon (primary production)

12.5 kg CO₂/kg
12 kg CO₂/kg

Embodied Water

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

Typical Recycled Content

60%
70%

Same in both: Embodied Energy (primary production) 200 MJ/kg85,985 BTU/lb

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

98 kN·m/kg
64 kN·m/kg

Specific Stiffness (E / density)

27.1 MN·m/kg
26.8 MN·m/kg

Modulus of Resilience

239 kJ/m³
35 kJ/m³

Thermal Diffusivity

58.7 mm²/s
50.9 mm²/s

Thermal Shock Resistance Index

25
15

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 scale356LM6

Manufacturing and finishing

Capability356LM6
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.

356 vs LM6 — frequently asked

Is 356 stronger than LM6?

Yes. 356 has a typical yield strength of 186 MPa (27 ksi) against 70 MPa (10.2 ksi) for LM6 — about 166% more. Tensile strength is 262 MPa (38 ksi) vs 170 MPa (24.7 ksi).

Which is cheaper, 356 or LM6?

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, 356 or LM6?

356. Its machinability rates very good (70/100) against fair (40/100) for LM6.

Ready to make it?

Upload a CAD file and FabDigit prices the part in 356 and LM6 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.