Cobalt-Chrome Alloy L605 vs Ultimet
Cobalt-Chrome Alloy · grade comparison
Cobalt-Chrome Alloy L605 and Ultimet are both cobalt-chrome alloy grades. Ultimet is the stronger of the two: yield strength 490 MPa (71.1 ksi) against 460 MPa (66.7 ksi) for L605, about 7% more. In exchange, L605 is the more ductile: elongation 58% versus 39% for Ultimet, and Ultimet is harder (277 HB vs 240 HB). Ultimet is lighter (8.47 g/cm³ vs 9.13 g/cm³ for L605) and L605 runs hotter in service (980°C vs 900°C continuous). On the shop floor, Ultimet sits in a lower cost tier (high, $$$$) than L605 (specialty, $$$$$).
L605Choose it when the part is bent, formed or impact-loaded, or when the part sees heat.
UltimetChoose it when strength drives the design, or when weight is the constraint.
L605 vs Ultimet: propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all cobalt-chrome alloy 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 cobalt-chrome alloy 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.
Elastic (Young's) Modulus
Shear Modulus
Bulk Modulus
Poisson's Ratio
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Reduction in Area
Fatigue Strength (Endurance Limit)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Rockwell B
Hardness, Vickers
Hardness, Rockwell C
Same in both: Shear Strength 620 MPa89.9 ksi
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
Specific Heat Capacity
Thermal Expansion (CTE, 20–100 °C)
Max Service Temperature (continuous)
Same in both: Latent Heat of Fusion 270 J/g116 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)
Same in both: Corrosion Resistance 82 / 100
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability Rating (AISI 1212 = 100 %)
Weldability
Castability
Brazeability / Solderability
Polishability
Same in both: Machinability 18 / 100 · Formability (cold) 60 / 100
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Carbon (primary production)
Embodied Water
Same in both: Typical Recycled Content 30%
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 cobalt-chrome alloy grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.
Manufacturing and finishing
| Capability | L605 | Ultimet |
|---|---|---|
| CNC machining | Yes | — |
| Default condition | Solution Annealed | — |
| Relative cost | $$$$$ Specialty | $$$$ High |
| Min. machined wall | — | — |
| Best machined surface | — | — |
| Electropolishing | Yes | — |
| Passivation (Stainless Steel) | Yes | — |
L605 vs Ultimet — frequently asked
Is Ultimet stronger than L605?
Yes. Ultimet has a typical yield strength of 490 MPa (71.1 ksi) against 460 MPa (66.7 ksi) for L605 — about 7% more. Tensile strength is 1,000 MPa (145 ksi) vs 1,010 MPa (146 ksi).
Which is cheaper, L605 or Ultimet?
Ultimet is the lower-cost material: it sits in the high tier ($$$$) while L605 is specialty ($$$$$). Part price depends far more on geometry, tolerance and quantity than on raw stock — upload a CAD file for a live quote.
When should I choose L605 over Ultimet?
Pick L605 when the part is bent, formed or impact-loaded, or when the part sees heat. Pick Ultimet when strength drives the design, or when weight is the constraint.
Ready to make it?
Upload a CAD file and FabDigit prices the part in L605 and Ultimet 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.