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Copper Alloy C71640 vs C74500

Copper Alloy · grade comparison

Copper Alloy C71640 and C74500 are both copper alloy grades. C74500 is the stronger of the two: yield strength 400 MPa (58 ksi) against 220 MPa (31.9 ksi) for C71640, about 82% more. In exchange, C71640 is the more ductile: elongation 35% versus 12% for C74500, and C74500 is harder (150 HB vs 120 HB). C71640 is stiffer (152 GPa vs 127 GPa) and C71640 runs hotter in service (300°C vs 180°C continuous). On the shop floor, C71640 welds better (excellent vs fair).

C71640Choose it when the part is bent, formed or impact-loaded, or when the part sees heat.

C74500Choose it when strength drives the design.

C71640 vs C74500: properties

C71640C74500

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

152 GPa22 Msi
127 GPa18.4 Msi

Shear Modulus

57 GPa8.3 Msi
48 GPa7 Msi

Bulk Modulus

140 GPa20.3 Msi
128 GPa18.6 Msi

Poisson's Ratio

0.32
0.33

Tensile Strength (Ultimate)

515 MPa74.7 ksi
510 MPa74 ksi

Yield Strength (0.2% offset)

220 MPa31.9 ksi
400 MPa58 ksi

Elongation at Break

35%
12%

Reduction in Area

60%
—

Shear Strength

340 MPa49.3 ksi
330 MPa47.9 ksi

Fatigue Strength (Endurance Limit)

170 MPa24.7 ksi
180 MPa26.1 ksi

Hardness, Brinell

120 HB
150 HB

Hardness, Rockwell B

68 HRB
80 HRB

Hardness, Vickers

125 HV
158 HV

Physical

Density and transition temperatures.

Density

8.94 g/cm³0.32 lb/in³
8.73 g/cm³0.32 lb/in³

Melting Point (Solidus)

1,171°C2,140 °F
954°C1,749 °F

Liquidus Temperature

1,238°C2,260 °F
1,021°C1,870 °F

Thermal

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

Thermal Conductivity

25 W/m·K14.4 BTU/hr·ft·°F
45 W/m·K26 BTU/hr·ft·°F

Thermal Expansion (CTE, 20–100 °C)

15.9 µm/m·K8.8 µin/in·°F
16.2 µm/m·K9 µin/in·°F

Latent Heat of Fusion

220 J/g94.6 BTU/lb
195 J/g83.8 BTU/lb

Max Service Temperature (continuous)

300°C572 °F
180°C356 °F

Same in both: Specific Heat Capacity 377 J/kg·K0.09 BTU/lb·°F · Min Service Temperature -200°C-328 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

4.3 % IACS
9 % IACS

Electrical Resistivity

4×10⁻⁷ Ω·m15.7 µΩ·in
1.92×10⁻⁷ Ω·m7.56 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

80 / 100
62 / 100

Same in both: Galvanic Potential (seawater, vs SCE) -0.26 V

Manufacturability

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

Machinability

28 / 100
30 / 100

Weldability

85 / 100
40 / 100

Formability (cold)

80 / 100
60 / 100

Castability

40 / 100
—

Brazeability / Solderability

75 / 100
88 / 100

Polishability

70 / 100
90 / 100

Same in both: Machinability Rating (AISI 1212 = 100 %) 20%

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

95 MJ/kg40,843 BTU/lb
78 MJ/kg33,534 BTU/lb

Embodied Carbon (primary production)

7.5 kg CO₂/kg
5.2 kg CO₂/kg

Embodied Water

350 L/kg41.9 gal/lb
260 L/kg31.2 gal/lb

Typical Recycled Content

30%
40%

Common Calculations

Ratios derived from the values above.

Specific Stiffness (E / density)

17 MN·m/kg
14.5 MN·m/kg

Modulus of Resilience

159 kJ/m³
630 kJ/m³

Thermal Diffusivity

7.4 mm²/s
13.7 mm²/s

Thermal Shock Resistance Index

5
11

Same in both: Specific Strength (UTS / density) 58 kN·m/kg

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 scaleC74500C71640

Manufacturing and finishing

CapabilityC71640C74500
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.

C71640 vs C74500 — frequently asked

Is C74500 stronger than C71640?

Yes. C74500 has a typical yield strength of 400 MPa (58 ksi) against 220 MPa (31.9 ksi) for C71640 — about 82% more. Tensile strength is 510 MPa (74 ksi) vs 515 MPa (74.7 ksi).

Which is cheaper, C71640 or C74500?

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, C71640 or C74500?

C71640. Its weldability rates excellent (85/100) against fair (40/100) for C74500.

Ready to make it?

Upload a CAD file and FabDigit prices the part in C71640 and C74500 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.