Copper Alloy C84400 vs C91700
Copper Alloy · grade comparison
Copper Alloy C84400 and C91700 are both copper alloy grades. C91700 is the stronger of the two: yield strength 172 MPa (24.9 ksi) against 110 MPa (16 ksi) for C84400, about 56% more; tensile strength follows at 310 MPa (45 ksi) vs 234 MPa (33.9 ksi). In exchange, C84400 is the more ductile: elongation 26% versus 12% for C91700, and C91700 is harder (95 HB vs 55 HB). C91700 is stiffer (105 GPa vs 95 GPa) and C91700 runs hotter in service (260°C vs 200°C continuous). On the shop floor, C84400 machines more easily (excellent vs fair) and C91700 sits in a lower cost tier (high, $$$$) than C84400 (specialty, $$$$$).
C84400Choose it when the part is bent, formed or impact-loaded, or when the part is machined in volume.
C91700Choose it when strength drives the design, or when the part sees heat.
C84400 vs C91700: 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
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Compressive Strength
Shear Strength
Fatigue Strength (Endurance Limit)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Rockwell B
Reduction in Area
Hardness, Vickers
Same in both: Bulk Modulus 115 GPa16.7 Msi · Poisson's Ratio 0.34
Physical
Density and transition temperatures.
Melting Point (Solidus)
Liquidus Temperature
Same in both: Density 8.8 g/cm³0.32 lb/in³
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Latent Heat of Fusion
Max Service Temperature (continuous)
Min Service Temperature
Same in both: Specific Heat Capacity 377 J/kg·K0.09 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 18 µm/m·K10 µin/in·°F
Electrical
Conductivity and insulation.
Electrical Conductivity
Electrical Resistivity
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Corrosion Resistance
Same in both: Galvanic Potential (seawater, vs SCE) -0.28 V
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
Polishability
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
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 | C84400 | C91700 |
|---|---|---|
| CNC machining | Yes | — |
| Default condition | As Cast | — |
| Relative cost | $$$$$ Specialty | $$$$ High |
| Min. machined wall | 0.8 mm | — |
| Best machined surface | Ra 1.6 µm | — |
| Chrome Plating | Yes | — |
| Electropolishing | Yes | — |
| Nickel Plating | Yes | — |
| Painting | Yes | — |
| Tin Plating | Yes | — |
They share 4 finishes: Copper Plating, Electroless Nickel (EN), Gold Plating, Silver Plating.
C84400 vs C91700 — frequently asked
Is C91700 stronger than C84400?
Yes. C91700 has a typical yield strength of 172 MPa (24.9 ksi) against 110 MPa (16 ksi) for C84400 — about 56% more. Tensile strength is 310 MPa (45 ksi) vs 234 MPa (33.9 ksi).
Which is cheaper, C84400 or C91700?
C91700 is the lower-cost material: it sits in the high tier ($$$$) while C84400 is specialty ($$$$$). Part price depends far more on geometry, tolerance and quantity than on raw stock — upload a CAD file for a live quote.
Which is easier to machine, C84400 or C91700?
C84400. Its machinability rates excellent (90/100) against fair (35/100) for C91700; for welding the order is C91700 first (poor, 25/100) then C84400 (poor, 20/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in C84400 and C91700 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.