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Copper Alloy C71580 vs C74400

Copper Alloy · grade comparison

Copper Alloy C71580 and C74400 are both copper alloy grades. C74400 is the stronger of the two: yield strength 440 MPa (63.8 ksi) against 150 MPa (21.8 ksi) for C71580, about 193% more; tensile strength follows at 515 MPa (74.7 ksi) vs 380 MPa (55.1 ksi). In exchange, C71580 is the more ductile: elongation 42% versus 12% for C74400, and C74400 is harder (138 HB vs 80 HB). C71580 is stiffer (152 GPa vs 124 GPa) and C71580 runs hotter in service (350°C vs 200°C continuous). On the shop floor, C71580 welds better (excellent vs fair).

C71580Choose it when the part is bent, formed or impact-loaded, or when the part sees heat.

C74400Choose it when strength drives the design.

C71580 vs C74400: properties

C71580C74400

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

152 GPa22 Msi
124 GPa18 Msi

Shear Modulus

57 GPa8.3 Msi
46 GPa6.7 Msi

Bulk Modulus

140 GPa20.3 Msi
130 GPa18.9 Msi

Poisson's Ratio

0.33
0.34

Tensile Strength (Ultimate)

380 MPa55.1 ksi
515 MPa74.7 ksi

Yield Strength (0.2% offset)

150 MPa21.8 ksi
440 MPa63.8 ksi

Elongation at Break

42%
12%

Reduction in Area

65%
—

Shear Strength

275 MPa39.9 ksi
340 MPa49.3 ksi

Fatigue Strength (Endurance Limit)

140 MPa20.3 ksi
200 MPa29 ksi

Charpy V-Notch Impact (RT)

120 J88.5 ft·lbf
—

Hardness, Brinell

80 HB
138 HB

Hardness, Rockwell B

40 HRB
75 HRB

Hardness, Vickers

85 HV
145 HV

Physical

Density and transition temperatures.

Density

8.94 g/cm³0.32 lb/in³
8.7 g/cm³0.31 lb/in³

Melting Point (Solidus)

1,170°C2,138 °F
1,020°C1,868 °F

Liquidus Temperature

1,240°C2,264 °F
1,065°C1,949 °F

Thermal

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

Thermal Conductivity

29 W/m·K16.8 BTU/hr·ft·°F
45 W/m·K26 BTU/hr·ft·°F

Latent Heat of Fusion

220 J/g94.6 BTU/lb
200 J/g86 BTU/lb

Max Service Temperature (continuous)

350°C662 °F
200°C392 °F

Min Service Temperature

-198°C-324 °F
-200°C-328 °F

Same in both: 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

Electrical

Conductivity and insulation.

Electrical Conductivity

4.6 % IACS
9.8 % IACS

Electrical Resistivity

3.75×10⁻⁷ Ω·m14.8 µΩ·in
1.76×10⁻⁷ Ω·m6.93 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.26 V
-0.2 V

Corrosion Resistance

82 / 100
62 / 100

Manufacturability

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

Machinability

28 / 100
25 / 100

Weldability

88 / 100
52 / 100

Formability (cold)

85 / 100
70 / 100

Castability

58 / 100
—

Brazeability / Solderability

78 / 100
85 / 100

Polishability

75 / 100
90 / 100

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

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

88 MJ/kg37,833 BTU/lb
62 MJ/kg26,655 BTU/lb

Embodied Carbon (primary production)

6.5 kg CO₂/kg
4.5 kg CO₂/kg

Typical Recycled Content

30%
35%

Same in both: Embodied Water 300 L/kg35.9 gal/lb

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

43 kN·m/kg
59 kN·m/kg

Specific Stiffness (E / density)

17 MN·m/kg
14.3 MN·m/kg

Modulus of Resilience

74 kJ/m³
781 kJ/m³

Thermal Diffusivity

8.6 mm²/s
13.7 mm²/s

Thermal Shock Resistance Index

4
12

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 scaleC74400C71580

Manufacturing and finishing

CapabilityC71580C74400
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.

C71580 vs C74400 — frequently asked

Is C74400 stronger than C71580?

Yes. C74400 has a typical yield strength of 440 MPa (63.8 ksi) against 150 MPa (21.8 ksi) for C71580 — about 193% more. Tensile strength is 515 MPa (74.7 ksi) vs 380 MPa (55.1 ksi).

Which is cheaper, C71580 or C74400?

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, C71580 or C74400?

C71580. Its weldability rates excellent (88/100) against fair (52/100) for C74400.

Ready to make it?

Upload a CAD file and FabDigit prices the part in C71580 and C74400 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.