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Copper Alloy C51900 vs C66100

Copper Alloy · grade comparison

Copper Alloy C51900 and C66100 are both copper alloy grades. C51900 is the stronger of the two: yield strength 450 MPa (65.3 ksi) against 380 MPa (55.1 ksi) for C66100, about 18% more. C51900 is the more ductile: elongation 20% versus 12% for C66100. C66100 is lighter (8.53 g/cm³ vs 8.8 g/cm³ for C51900) and C51900 conducts heat better (67 W/m·K vs 57 W/m·K). On the shop floor, C66100 machines more easily (good vs poor), C51900 welds better (fair vs poor), and C66100 sits in a lower cost tier (high, $$$$) than C51900 (specialty, $$$$$).

C51900Choose it when strength drives the design, or when the part is bent, formed or impact-loaded.

C66100Choose it when weight is the constraint, or when the part is machined in volume.

C51900 vs C66100: properties

C51900C66100

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

115 GPa16.7 Msi
117 GPa17 Msi

Shear Modulus

43 GPa6.2 Msi
44 GPa6.4 Msi

Bulk Modulus

120 GPa17.4 Msi
115 GPa16.7 Msi

Tensile Strength (Ultimate)

520 MPa75.4 ksi
515 MPa74.7 ksi

Yield Strength (0.2% offset)

450 MPa65.3 ksi
380 MPa55.1 ksi

Elongation at Break

20%
12%

Reduction in Area

35%
—

Compressive Strength

450 MPa65.3 ksi
—

Shear Strength

340 MPa49.3 ksi
320 MPa46.4 ksi

Fatigue Strength (Endurance Limit)

200 MPa29 ksi
190 MPa27.6 ksi

Hardness, Brinell

155 HB
150 HB

Hardness, Rockwell B

78 HRB
80 HRB

Hardness, Vickers

165 HV
—

Same in both: Poisson's Ratio 0.34

Physical

Density and transition temperatures.

Density

8.8 g/cm³0.32 lb/in³
8.53 g/cm³0.31 lb/in³

Melting Point (Solidus)

910°C1,670 °F
971°C1,780 °F

Liquidus Temperature

1,040°C1,904 °F
1,027°C1,881 °F

Thermal

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

Thermal Conductivity

67 W/m·K38.7 BTU/hr·ft·°F
57 W/m·K32.9 BTU/hr·ft·°F

Thermal Expansion (CTE, 20–100 °C)

18.5 µm/m·K10.3 µin/in·°F
18.4 µm/m·K10.2 µin/in·°F

Latent Heat of Fusion

175 J/g75.2 BTU/lb
205 J/g88.1 BTU/lb

Same in both: Specific Heat Capacity 377 J/kg·K0.09 BTU/lb·°F · Max Service Temperature (continuous) 200°C392 °F · Min Service Temperature -200°C-328 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

15 % IACS
12 % IACS

Electrical Resistivity

1.15×10⁻⁷ Ω·m4.53 µΩ·in
1.44×10⁻⁷ Ω·m5.67 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.28 V
-0.26 V

Same in both: Corrosion Resistance 70 / 100

Manufacturability

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

Machinability

25 / 100
55 / 100

Machinability Rating (AISI 1212 = 100 %)

20%
50%

Weldability

45 / 100
30 / 100

Formability (cold)

55 / 100
45 / 100

Brazeability / Solderability

90 / 100
75 / 100

Polishability

80 / 100
70 / 100

Castability

—
35 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

62 MJ/kg26,655 BTU/lb
60 MJ/kg25,795 BTU/lb

Embodied Carbon (primary production)

4.2 kg CO₂/kg
3.6 kg CO₂/kg

Same in both: Embodied Water 320 L/kg38.3 gal/lb · Typical Recycled Content 40%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

59 kN·m/kg
60 kN·m/kg

Specific Stiffness (E / density)

13.1 MN·m/kg
13.7 MN·m/kg

Modulus of Resilience

880 kJ/m³
617 kJ/m³

Thermal Diffusivity

20.2 mm²/s
17.7 mm²/s

Thermal Shock Resistance Index

16
14

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 scaleC51900C66100

Manufacturing and finishing

CapabilityC51900C66100
CNC machiningYes—
Sheet metalYes—
Default condition——
Relative cost$$$$$ Specialty$$$$ High
Min. machined wall0.8 mm—
Best machined surfaceRa 1.6 µm—
Chrome PlatingYes—
ElectropolishingYes—
Nickel PlatingYes—
PaintingYes—
Tin PlatingYes—

They share 4 finishes: Copper Plating, Electroless Nickel (EN), Gold Plating, Silver Plating.

C51900 vs C66100 — frequently asked

Is C51900 stronger than C66100?

Yes. C51900 has a typical yield strength of 450 MPa (65.3 ksi) against 380 MPa (55.1 ksi) for C66100 — about 18% more. Tensile strength is 520 MPa (75.4 ksi) vs 515 MPa (74.7 ksi).

Which is cheaper, C51900 or C66100?

C66100 is the lower-cost material: it sits in the high tier ($$$$) while C51900 is specialty ($$$$$). Part price depends far more on geometry, tolerance and quantity than on raw stock — upload a CAD file for a live quote.

Which is easier to machine, C51900 or C66100?

C66100. Its machinability rates good (55/100) against poor (25/100) for C51900; for welding the order is C51900 first (fair, 45/100) then C66100 (poor, 30/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in C51900 and C66100 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.