Copper Alloy C18400-O61 vs C18400-TD04
Copper Alloy · C18400 temper comparison
C18400-O61 and C18400-TD04 are two conditions of the same copper alloy grade, C18400: O61 (annealed) versus TD04 (solution heat treated and cold worked, full hard). The chemistry is identical, so every difference below comes from the condition. C18400-TD04 is the stronger of the two: yield strength 390 MPa (56.6 ksi) against 85 MPa (12.3 ksi) for C18400-O61, about 4.6 times as much; tensile strength follows at 430 MPa (62.4 ksi) vs 230 MPa (33.4 ksi). In exchange, C18400-O61 is the more ductile: elongation 42% versus 10% for C18400-TD04, and C18400-TD04 is harder (125 HB vs 55 HB). C18400-O61 runs hotter in service (350°C vs 250°C continuous).
C18400-O61Choose it when the part is bent, formed or impact-loaded, or when the part sees heat.
C18400-TD04Choose it when strength drives the design.
C18400-O61 vs C18400-TD04: 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.
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Reduction in Area
Shear Strength
Fatigue Strength (Endurance Limit)
Hardness, Brinell
Hardness, Rockwell B
Same in both: Elastic (Young's) Modulus 115 GPa16.7 Msi · Shear Modulus 44 GPa6.4 Msi · Bulk Modulus 138 GPa20 Msi · Poisson's Ratio 0.34
Physical
Density and transition temperatures.
Same in both: Density 8.89 g/cm³0.32 lb/in³ · Melting Point (Solidus) 1,070°C1,958 °F · Liquidus Temperature 1,080°C1,976 °F
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Max Service Temperature (continuous)
Same in both: Specific Heat Capacity 385 J/kg·K0.09 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 17 µm/m·K9.4 µin/in·°F · Latent Heat of Fusion 205 J/g88.1 BTU/lb · Min Service Temperature -200°C-328 °F
Electrical
Conductivity and insulation.
Electrical Conductivity
Electrical Resistivity
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Galvanic Potential (seawater, vs SCE) -0.28 V · Corrosion Resistance 68 / 100
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Machinability Rating (AISI 1212 = 100 %)
Formability (cold)
Same in both: Weldability 45 / 100 · Castability 55 / 100 · Brazeability / Solderability 70 / 100 · Polishability 70 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 57 MJ/kg24,506 BTU/lb · Embodied Carbon (primary production) 3.8 kg CO₂/kg · Embodied Water 250 L/kg30 gal/lb · Typical Recycled Content 30%
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.
C18400-O61 vs C18400-TD04 — frequently asked
Is C18400-TD04 stronger than C18400-O61?
Yes. C18400-TD04 has a typical yield strength of 390 MPa (56.6 ksi) against 85 MPa (12.3 ksi) for C18400-O61 — about 4.6 times as much. Tensile strength is 430 MPa (62.4 ksi) vs 230 MPa (33.4 ksi).
Which condition does FabDigit quote by default, O61 or TD04?
TF00 is the default C18400 condition in the FabDigit quote flow (neither O61 nor TD04). The other condition is available on request or by drawing note — specify it in the material field or the part notes and the quote is priced for it.
Which is easier to machine, C18400-O61 or C18400-TD04?
C18400-TD04, by a small margin. Both rate fair for machinability — 42/100 against 35/100 for C18400-O61.
Ready to make it?
Upload a CAD file and FabDigit prices the part in C18400-O61 and C18400-TD04 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.