Aluminum 355 vs LM6
Aluminum · grade comparison
Aluminum 355 and LM6 are both aluminum grades, both cast al. 355 is the stronger of the two: yield strength 180 MPa (26.1 ksi) against 70 MPa (10.2 ksi) for LM6, about 157% more; tensile strength follows at 250 MPa (36.3 ksi) vs 170 MPa (24.7 ksi). In exchange, LM6 is the more ductile: elongation 6% versus 3% for 355, and 355 is harder (85 HB vs 52 HB). 355 runs hotter in service (175°C vs 150°C continuous) and 355 conducts heat better (151 W/m·K vs 130 W/m·K). On the shop floor, 355 machines more easily (good vs fair) and LM6 welds better (very good vs good).
355Choose it when strength drives the design, or when the part sees heat.
LM6Choose it when the part is bent, formed or impact-loaded, or when it will be welded.
355 vs LM6: propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all aluminum grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
How to read these bars
- One bar per material. A full bar is the highest value among all aluminum grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Bulk Modulus
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Shear Strength
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
Hardness, Brinell
Charpy V-Notch Impact (RT)
Hardness, Vickers
Same in both: Elastic (Young's) Modulus 71 GPa10.3 Msi · Shear Modulus 26.5 GPa3.8 Msi · Poisson's Ratio 0.33
Physical
Density and transition temperatures.
Density
Melting Point (Solidus)
Liquidus Temperature
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Thermal Expansion (CTE, 20–100 °C)
Max Service Temperature (continuous)
Same in both: Specific Heat Capacity 963 J/kg·K0.23 BTU/lb·°F · Latent Heat of Fusion 389 J/g167 BTU/lb · Min Service Temperature -196°C-321 °F
Electrical
Conductivity and insulation.
Electrical Conductivity
Electrical Resistivity
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Galvanic Potential (seawater, vs SCE)
Corrosion Resistance
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Machinability Rating (AISI 1212 = 100 %)
Weldability
Castability
Brazeability / Solderability
Polishability
Same in both: Formability (cold) 5 / 100
Sustainability
Primary-production footprint per kilogram.
Typical Recycled Content
Same in both: Embodied Energy (primary production) 200 MJ/kg85,985 BTU/lb · Embodied Carbon (primary production) 12 kg CO₂/kg · Embodied Water 1,100 L/kg132 gal/lb
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Specific Stiffness (E / density)
Modulus of Resilience
Thermal Diffusivity
Thermal Shock Resistance Index
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.
Manufacturing and finishing
| Capability | 355 | LM6 |
|---|---|---|
| Default condition | — | F |
| Relative cost | $ Budget | $ Budget |
| Min. machined wall | 0.5 mm | 0.5 mm |
| Best machined surface | Ra 0.8 µm | Ra 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 LM6 — frequently asked
Is 355 stronger than LM6?
Yes. 355 has a typical yield strength of 180 MPa (26.1 ksi) against 70 MPa (10.2 ksi) for LM6 — about 157% more. Tensile strength is 250 MPa (36.3 ksi) vs 170 MPa (24.7 ksi).
Which is cheaper, 355 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, 355 or LM6?
355. Its machinability rates good (62/100) against fair (40/100) for LM6; for welding the order is LM6 first (very good, 80/100) then 355 (good, 55/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in 355 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.