Copper Alloy C55281 vs ERCuSi-A
Copper Alloy · grade comparison
Copper Alloy C55281 and ERCuSi-A are both copper alloy grades. ERCuSi-A is the stronger of the two: yield strength 195 MPa (28.3 ksi) against 170 MPa (24.7 ksi) for C55281, about 15% more; tensile strength follows at 350 MPa (50.8 ksi) vs 250 MPa (36.3 ksi). ERCuSi-A is the more ductile: elongation 38% versus 6% for C55281. C55281 is lighter (8.1 g/cm³ vs 8.53 g/cm³ for ERCuSi-A) and ERCuSi-A runs hotter in service (200°C vs 150°C continuous).
C55281Choose it when weight is the constraint.
ERCuSi-AChoose it when strength drives the design, or when the part is bent, formed or impact-loaded.
C55281 vs ERCuSi-A: propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all copper 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 copper 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
Poisson's Ratio
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Shear Strength
Reduction in Area
Fatigue Strength (Endurance Limit)
Charpy V-Notch Impact (RT)
Hardness, Rockwell B
Hardness, Vickers
Same in both: Bulk Modulus 115 GPa16.7 Msi · Hardness, Brinell 85 HB
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)
Latent Heat of Fusion
Max Service Temperature (continuous)
Min Service Temperature
Same in both: Specific Heat Capacity 380 J/kg·K0.09 BTU/lb·°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.
Formability (cold)
Castability
Brazeability / Solderability
Polishability
Machinability
Machinability Rating (AISI 1212 = 100 %)
Weldability
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Carbon (primary production)
Embodied Water
Typical Recycled Content
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 7
Strength versus weight
Yield strength against density for every copper alloy grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.
Manufacturing and finishing
| Capability | C55281 | ERCuSi-A |
|---|---|---|
| Default condition | — | — |
| Relative cost | $$$$ High | $$$$ High |
| Min. machined wall | — | — |
| Best machined surface | — | — |
Both take the same 4 finishes: Copper Plating, Electroless Nickel (EN), Gold Plating, Silver Plating.
C55281 vs ERCuSi-A — frequently asked
Is ERCuSi-A stronger than C55281?
Yes. ERCuSi-A has a typical yield strength of 195 MPa (28.3 ksi) against 170 MPa (24.7 ksi) for C55281 — about 15% more. Tensile strength is 350 MPa (50.8 ksi) vs 250 MPa (36.3 ksi).
Which is cheaper, C55281 or ERCuSi-A?
Both sit in the same relative cost tier ($$$$, high); the part price will be decided by machining time, tolerance and quantity rather than by the material.
When should I choose C55281 over ERCuSi-A?
Pick C55281 when weight is the constraint. Pick ERCuSi-A when strength drives the design, or when the part is bent, formed or impact-loaded.
Ready to make it?
Upload a CAD file and FabDigit prices the part in C55281 and ERCuSi-A 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.