FabDigitFabDigit

Copper Alloy C70700 vs C74500

Copper Alloy · grade comparison

Copper Alloy C70700 and C74500 are both copper alloy grades. C74500 is the stronger of the two: yield strength 400 MPa (58 ksi) against 115 MPa (16.7 ksi) for C70700, about 3.5 times as much; tensile strength follows at 510 MPa (74 ksi) vs 310 MPa (45 ksi). In exchange, C70700 is the more ductile: elongation 42% versus 12% for C74500, and C74500 is harder (150 HB vs 65 HB). C70700 runs hotter in service (350°C vs 180°C continuous) and C74500 conducts heat better (45 W/m·K vs 40 W/m·K). On the shop floor, C70700 welds better (excellent vs fair).

C70700Choose it when the part is bent, formed or impact-loaded, or when the part sees heat.

C74500Choose it when strength drives the design.

C70700 vs C74500: properties

C70700C74500

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

124 GPa18 Msi
127 GPa18.4 Msi

Shear Modulus

46 GPa6.7 Msi
48 GPa7 Msi

Bulk Modulus

112 GPa16.2 Msi
128 GPa18.6 Msi

Poisson's Ratio

0.31
0.33

Tensile Strength (Ultimate)

310 MPa45 ksi
510 MPa74 ksi

Yield Strength (0.2% offset)

115 MPa16.7 ksi
400 MPa58 ksi

Elongation at Break

42%
12%

Reduction in Area

65%
—

Shear Strength

220 MPa31.9 ksi
330 MPa47.9 ksi

Fatigue Strength (Endurance Limit)

140 MPa20.3 ksi
180 MPa26.1 ksi

Charpy V-Notch Impact (RT)

120 J88.5 ft·lbf
—

Hardness, Brinell

65 HB
150 HB

Hardness, Rockwell B

30 HRB
80 HRB

Hardness, Vickers

75 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)

1,100°C2,012 °F
954°C1,749 °F

Liquidus Temperature

1,145°C2,093 °F
1,021°C1,870 °F

Thermal

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

Thermal Conductivity

40 W/m·K23.1 BTU/hr·ft·°F
45 W/m·K26 BTU/hr·ft·°F

Thermal Expansion (CTE, 20–100 °C)

17.1 µm/m·K9.5 µin/in·°F
16.2 µm/m·K9 µin/in·°F

Latent Heat of Fusion

210 J/g90.3 BTU/lb
195 J/g83.8 BTU/lb

Max Service Temperature (continuous)

350°C662 °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

9.5 % IACS
9 % IACS

Electrical Resistivity

1.9×10⁻⁷ Ω·m7.48 µΩ·in
1.92×10⁻⁷ Ω·m7.56 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.28 V
-0.26 V

Corrosion Resistance

78 / 100
62 / 100

Manufacturability

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

Weldability

88 / 100
40 / 100

Formability (cold)

90 / 100
60 / 100

Castability

45 / 100
—

Polishability

70 / 100
90 / 100

Same in both: Machinability 30 / 100 · Machinability Rating (AISI 1212 = 100 %) 20% · Brazeability / Solderability 88 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

70 MJ/kg30,095 BTU/lb
78 MJ/kg33,534 BTU/lb

Embodied Carbon (primary production)

4.8 kg CO₂/kg
5.2 kg CO₂/kg

Typical Recycled Content

30%
40%

Same in both: Embodied Water 260 L/kg31.2 gal/lb

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

35 kN·m/kg
58 kN·m/kg

Specific Stiffness (E / density)

13.9 MN·m/kg
14.5 MN·m/kg

Modulus of Resilience

53 kJ/m³
630 kJ/m³

Thermal Diffusivity

11.9 mm²/s
13.7 mm²/s

Thermal Shock Resistance Index

6
11

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 scaleC74500C70700

Manufacturing and finishing

CapabilityC70700C74500
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.

C70700 vs C74500 — frequently asked

Is C74500 stronger than C70700?

Yes. C74500 has a typical yield strength of 400 MPa (58 ksi) against 115 MPa (16.7 ksi) for C70700 — about 3.5 times as much. Tensile strength is 510 MPa (74 ksi) vs 310 MPa (45 ksi).

Which is cheaper, C70700 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, C70700 or C74500?

C70700. Its weldability rates excellent (88/100) against fair (40/100) for C74500.

Ready to make it?

Upload a CAD file and FabDigit prices the part in C70700 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.