Copper Alloy ERCu vs ERCuSi-A
Copper Alloy · grade comparison
Copper Alloy ERCu and ERCuSi-A are both copper alloy grades. ERCuSi-A is the stronger of the two: yield strength 195 MPa (28.3 ksi) against 80 MPa (11.6 ksi) for ERCu, about 144% more; tensile strength follows at 350 MPa (50.8 ksi) vs 225 MPa (32.6 ksi). ERCuSi-A is harder — 85 HB against 55 HB for ERCu — which matters for wear surfaces and threads. ERCuSi-A is lighter (8.53 g/cm³ vs 8.9 g/cm³ for ERCu) and ERCu is stiffer (115 GPa vs 103 GPa). On the shop floor, ERCuSi-A welds better (excellent vs very good) and ERCu forms better (excellent vs very good).
ERCuChoose it when the part sees heat.
ERCuSi-AChoose it when strength drives the design, or when surface hardness matters.
ERCu 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
Bulk Modulus
Poisson's Ratio
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Reduction in Area
Shear Strength
Fatigue Strength (Endurance Limit)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Vickers
Hardness, Rockwell B
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 205 J/g88.1 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
Polishability
Same in both: Brazeability / Solderability 92 / 100
Sustainability
Primary-production footprint per kilogram.
Embodied Water
Typical Recycled Content
Same in both: Embodied Energy (primary production) 57 MJ/kg24,506 BTU/lb · Embodied Carbon (primary production) 3.8 kg CO₂/kg
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 copper alloy grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.
Manufacturing and finishing
| Capability | ERCu | ERCuSi-A |
|---|---|---|
| Default condition | — | — |
| Relative cost | $$$$ High | $$$$ High |
| Min. machined wall | — | — |
| Best machined surface | — | — |
Both take the same 4 finishes: Copper Plating, Electroless Nickel (EN), Gold Plating, Silver Plating.
ERCu vs ERCuSi-A — frequently asked
Is ERCuSi-A stronger than ERCu?
Yes. ERCuSi-A has a typical yield strength of 195 MPa (28.3 ksi) against 80 MPa (11.6 ksi) for ERCu — about 144% more. Tensile strength is 350 MPa (50.8 ksi) vs 225 MPa (32.6 ksi).
Which is cheaper, ERCu or ERCuSi-A?
Both sit in the same relative cost tier ($$$$, high); the part price will be decided by machining time, tolerance and quantity rather than by the material.
Which welds better, ERCu or ERCuSi-A?
ERCuSi-A. Its weldability rates excellent (90/100) against very good (78/100) for ERCu.
Ready to make it?
Upload a CAD file and FabDigit prices the part in ERCu 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.