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Aluminum 356 vs LM20

Aluminum · grade comparison

Aluminum 356 and LM20 are both aluminum grades. 356 is the stronger of the two: yield strength 186 MPa (27 ksi) against 135 MPa (19.6 ksi) for LM20, about 38% more. 356 is the more ductile: elongation 5% versus 3% for LM20. 356 conducts heat better (151 W/m·K vs 121 W/m·K). On the shop floor, 356 machines more easily (very good vs fair), 356 welds better (very good vs good), and 356 sits in a lower cost tier (budget, $) than LM20 (standard, $$).

356Choose it when strength drives the design, or when the part is bent, formed or impact-loaded.

356 vs LM20: properties

356LM20

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
260 MPa37.7 ksi

Yield Strength (0.2% offset)

186 MPa27 ksi
135 MPa19.6 ksi

Elongation at Break

5%
3%

Compressive Strength

190 MPa27.6 ksi
—

Shear Strength

179 MPa26 ksi
170 MPa24.7 ksi

Fatigue Strength (Endurance Limit)

90 MPa13.1 ksi
130 MPa18.9 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
78 HB

Same in both: Poisson's Ratio 0.33

Physical

Density and transition temperatures.

Density

2.67 g/cm³0.1 lb/in³
2.66 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
121 W/m·K69.9 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

Latent Heat of Fusion

389 J/g167 BTU/lb
515 J/g221 BTU/lb

Same in both: Specific Heat Capacity 963 J/kg·K0.23 BTU/lb·°F · Max Service Temperature (continuous) 150°C302 °F · Min Service Temperature -196°C-321 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

39 % IACS
31 % IACS

Electrical Resistivity

4.4×10⁻⁸ Ω·m1.73 µΩ·in
5.6×10⁻⁸ Ω·m2.2 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

62 / 100
58 / 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
35 / 100

Machinability Rating (AISI 1212 = 100 %)

120%
40%

Weldability

78 / 100
55 / 100

Brazeability / Solderability

30 / 100
35 / 100

Polishability

45 / 100
40 / 100

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

Sustainability

Primary-production footprint per kilogram.

Embodied Carbon (primary production)

12.5 kg CO₂/kg
12 kg CO₂/kg

Typical Recycled Content

60%
85%

Same in both: Embodied Energy (primary production) 200 MJ/kg85,985 BTU/lb · Embodied Water 1,200 L/kg144 gal/lb

Common Calculations

Ratios derived from the values above.

Specific Stiffness (E / density)

27.1 MN·m/kg
26.7 MN·m/kg

Modulus of Resilience

239 kJ/m³
128 kJ/m³

Thermal Diffusivity

58.7 mm²/s
47.2 mm²/s

Thermal Shock Resistance Index

25
22

Same in both: Specific Strength (UTS / density) 98 kN·m/kg

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 scale356LM20

Manufacturing and finishing

Capability356LM20
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.

356 vs LM20 — frequently asked

Is 356 stronger than LM20?

Yes. 356 has a typical yield strength of 186 MPa (27 ksi) against 135 MPa (19.6 ksi) for LM20 — about 38% more. Tensile strength is 262 MPa (38 ksi) vs 260 MPa (37.7 ksi).

Which is cheaper, 356 or LM20?

356 is the lower-cost material: it sits in the budget tier ($) while LM20 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 LM20?

356. Its machinability rates very good (70/100) against fair (35/100) for LM20; for welding the order is 356 first (very good, 78/100) then LM20 (good, 55/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in 356 and LM20 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.