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Copper Alloy C73500-H04 vs C73500-O61

Copper Alloy · C73500 temper comparison

C73500-H04 and C73500-O61 are two conditions of the same copper alloy grade, C73500: H04 (full hard) versus O61 (annealed). The chemistry is identical, so every difference below comes from the condition. C73500-H04 is the stronger of the two: yield strength 525 MPa (76.1 ksi) against 145 MPa (21 ksi) for C73500-O61, about 3.6 times as much; tensile strength follows at 585 MPa (84.8 ksi) vs 385 MPa (55.8 ksi). In exchange, C73500-O61 is the more ductile: elongation 40% versus 4% for C73500-H04, and C73500-H04 is harder (160 HB vs 78 HB). C73500-O61 runs hotter in service (250°C vs 150°C continuous).

C73500-H04Choose it when strength drives the design.

C73500-O61Choose it when the part is bent, formed or impact-loaded, or when the part sees heat.

C73500-H04 vs C73500-O61: properties

C73500-H04C73500-O61

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Tensile Strength (Ultimate)

585 MPa84.8 ksi
385 MPa55.8 ksi

Yield Strength (0.2% offset)

525 MPa76.1 ksi
145 MPa21 ksi

Elongation at Break

4%
40%

Shear Strength

375 MPa54.4 ksi
275 MPa39.9 ksi

Fatigue Strength (Endurance Limit)

235 MPa34.1 ksi
150 MPa21.8 ksi

Hardness, Brinell

160 HB
78 HB

Hardness, Rockwell B

82 HRB
35 HRB

Hardness, Vickers

175 HV
140 HV

Same in both: Elastic (Young's) Modulus 127 GPa18.4 Msi · Shear Modulus 47 GPa6.8 Msi · Bulk Modulus 128 GPa18.6 Msi · Poisson's Ratio 0.34

Physical

Density and transition temperatures.

Same in both: Density 8.86 g/cm³0.32 lb/in³ · Melting Point (Solidus) 1,080°C1,976 °F · Liquidus Temperature 1,110°C2,030 °F

Thermal

How each material carries heat and how hot it can run.

Max Service Temperature (continuous)

150°C302 °F
250°C482 °F

Same in both: Thermal Conductivity 33 W/m·K19.1 BTU/hr·ft·°F · Specific Heat Capacity 377 J/kg·K0.09 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 16.2 µm/m·K9 µin/in·°F · Latent Heat of Fusion 210 J/g90.3 BTU/lb · Min Service Temperature -200°C-328 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

6 % IACS
6.5 % IACS

Same in both: Electrical Resistivity 2.78×10⁻⁷ Ω·m10.9 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Same in both: Galvanic Potential (seawater, vs SCE) -0.25 V · Corrosion Resistance 62 / 100

Manufacturability

FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.

Machinability

32 / 100
25 / 100

Formability (cold)

35 / 100
90 / 100

Same in both: Machinability Rating (AISI 1212 = 100 %) 20% · Weldability 55 / 100 · Castability 40 / 100 · Brazeability / Solderability 85 / 100 · Polishability 90 / 100

Sustainability

Primary-production footprint per kilogram.

Same in both: Embodied Energy (primary production) 78 MJ/kg33,534 BTU/lb · Embodied Carbon (primary production) 5.6 kg CO₂/kg · Embodied Water 250 L/kg30 gal/lb · Typical Recycled Content 35%

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.

501002005001,0007.588.599.5Density (g/cm³)Yield strength (MPa) — log scaleC73500

C73500-H04 vs C73500-O61 — frequently asked

Is C73500-H04 stronger than C73500-O61?

Yes. C73500-H04 has a typical yield strength of 525 MPa (76.1 ksi) against 145 MPa (21 ksi) for C73500-O61 — about 3.6 times as much. Tensile strength is 585 MPa (84.8 ksi) vs 385 MPa (55.8 ksi).

Which condition does FabDigit quote by default, H04 or O61?

H02 is the default C73500 condition in the FabDigit quote flow (neither H04 nor O61). 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, C73500-H04 or C73500-O61?

C73500-H04, by a small margin. Both rate poor for machinability — 32/100 against 25/100 for C73500-O61.

Ready to make it?

Upload a CAD file and FabDigit prices the part in C73500-H04 and C73500-O61 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.