Aluminum 355 vs LM25
Aluminum · grade comparison
Aluminum 355 and LM25 are both aluminum grades, both cast al. LM25 is the stronger of the two: yield strength 215 MPa (31.2 ksi) against 180 MPa (26.1 ksi) for 355, about 19% more. LM25 is harder — 95 HB against 85 HB for 355 — which matters for wear surfaces and threads. 355 runs hotter in service (175°C vs 150°C continuous). On the shop floor, LM25 welds better (very good vs good) and 355 sits in a lower cost tier (budget, $) than LM25 (standard, $$).
355Choose it when the part sees heat, or when cost is the deciding factor.
LM25Choose it when strength drives the design, or when surface hardness matters.
355 vs LM25: 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
Yield Strength (0.2% offset)
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 · Tensile Strength (Ultimate) 250 MPa36.3 ksi · Elongation at Break 3%
Physical
Density and transition temperatures.
Density
Melting Point (Solidus)
Liquidus Temperature
Thermal
How each material carries heat and how hot it can run.
Thermal Expansion (CTE, 20–100 °C)
Max Service Temperature (continuous)
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 · 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
Formability (cold)
Castability
Brazeability / Solderability
Same in both: Polishability 45 / 100
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Water
Typical Recycled Content
Same in both: Embodied Carbon (primary production) 12 kg CO₂/kg
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Specific Stiffness (E / density)
Modulus of Resilience
Thermal Diffusivity
Same in both: Thermal Shock Resistance Index 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.
Manufacturing and finishing
| Capability | 355 | LM25 |
|---|---|---|
| Default condition | — | T6 |
| Relative cost | $ Budget | $$ Standard |
| 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 LM25 — frequently asked
Is LM25 stronger than 355?
Yes. LM25 has a typical yield strength of 215 MPa (31.2 ksi) against 180 MPa (26.1 ksi) for 355 — about 19% more. Tensile strength is 250 MPa (36.3 ksi) vs 250 MPa (36.3 ksi).
Which is cheaper, 355 or LM25?
355 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 welds better, 355 or LM25?
LM25. Its weldability rates very good (75/100) against good (55/100) for 355.
Ready to make it?
Upload a CAD file and FabDigit prices the part in 355 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.