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Refractory Metal Cb-752 vs Pure Nb

Refractory Metal · grade comparison

Refractory Metal Cb-752 and Pure Nb are both refractory metal grades. Cb-752 is the stronger of the two: yield strength 310 MPa (45 ksi) against 125 MPa (18.1 ksi) for Pure Nb, about 148% more; tensile strength follows at 450 MPa (65.3 ksi) vs 220 MPa (31.9 ksi). In exchange, Pure Nb is the more ductile: elongation 40% versus 25% for Cb-752, and Cb-752 is harder (170 HB vs 80 HB). Pure Nb is lighter (8.57 g/cm³ vs 9.03 g/cm³ for Cb-752) and Cb-752 is stiffer (110 GPa vs 103 GPa). On the shop floor, Pure Nb welds better (80 vs 70 out of 100) and Cb-752 sits in a lower cost tier (high, $$$$) than Pure Nb (specialty, $$$$$).

Cb-752Choose it when strength drives the design, or when the part sees heat.

Pure NbChoose it when the part is bent, formed or impact-loaded, or when weight is the constraint.

Cb-752 vs Pure Nb: properties

Cb-752Pure Nb

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

110 GPa16 Msi
103 GPa14.9 Msi

Shear Modulus

40 GPa5.8 Msi
37.5 GPa5.4 Msi

Poisson's Ratio

0.38
0.4

Tensile Strength (Ultimate)

450 MPa65.3 ksi
220 MPa31.9 ksi

Yield Strength (0.2% offset)

310 MPa45 ksi
125 MPa18.1 ksi

Elongation at Break

25%
40%

Reduction in Area

55%
80%

Compressive Strength

320 MPa46.4 ksi
—

Shear Strength

290 MPa42.1 ksi
130 MPa18.9 ksi

Fatigue Strength (Endurance Limit)

220 MPa31.9 ksi
125 MPa18.1 ksi

Fracture Toughness (K_IC)

70 MPa·√m63.7 ksi·√in
—

Charpy V-Notch Impact (RT)

40 J29.5 ft·lbf
—

Hardness, Brinell

170 HB
80 HB

Hardness, Rockwell B

88 HRB
40 HRB

Hardness, Vickers

180 HV
80 HV

Same in both: Bulk Modulus 170 GPa24.7 Msi

Physical

Density and transition temperatures.

Density

9.03 g/cm³0.33 lb/in³
8.57 g/cm³0.31 lb/in³

Melting Point (Solidus)

2,470°C4,478 °F
2,477°C4,491 °F

Liquidus Temperature

2,500°C4,532 °F
2,477°C4,491 °F

Thermal

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

Thermal Conductivity

40 W/m·K23.1 BTU/hr·ft·°F
53.7 W/m·K31 BTU/hr·ft·°F

Specific Heat Capacity

270 J/kg·K0.06 BTU/lb·°F
265 J/kg·K0.06 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

7.1 µm/m·K3.9 µin/in·°F
7.3 µm/m·K4.1 µin/in·°F

Latent Heat of Fusion

285 J/g123 BTU/lb
290 J/g125 BTU/lb

Max Service Temperature (continuous)

1,400°C2,552 °F
400°C752 °F

Min Service Temperature

-196°C-321 °F
-269°C-452 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

7.2 % IACS
12 % IACS

Electrical Resistivity

2.4×10⁻⁷ Ω·m9.45 µΩ·in
1.45×10⁻⁷ Ω·m5.71 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

72 / 100
90 / 100

Galvanic Potential (seawater, vs SCE)

—
-0.15 V

Manufacturability

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

Machinability

30 / 100
28 / 100

Weldability

70 / 100
80 / 100

Formability (cold)

75 / 100
92 / 100

Polishability

60 / 100
85 / 100

Castability

—
20 / 100

Same in both: Machinability Rating (AISI 1212 = 100 %) 25% · Brazeability / Solderability 60 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

950 MJ/kg408,427 BTU/lb
500 MJ/kg214,962 BTU/lb

Embodied Carbon (primary production)

62 kg CO₂/kg
32 kg CO₂/kg

Embodied Water

—
400 L/kg47.9 gal/lb

Same in both: Typical Recycled Content 25%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

50 kN·m/kg
26 kN·m/kg

Specific Stiffness (E / density)

12.2 MN·m/kg
12 MN·m/kg

Modulus of Resilience

437 kJ/m³
76 kJ/m³

Thermal Diffusivity

16.4 mm²/s
23.6 mm²/s

Thermal Shock Resistance Index

23
16

Strength versus weight

Yield strength against density for every refractory metal grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.

1502003005007001,0001,5005101520Density (g/cm³)Yield strength (MPa) — log scalePure NbCb-752

Manufacturing and finishing

CapabilityCb-752Pure Nb
Default condition—Vacuum Annealed
Relative cost$$$$ High$$$$$ Specialty
Min. machined wall——
Best machined surface——

Cb-752 vs Pure Nb — frequently asked

Is Cb-752 stronger than Pure Nb?

Yes. Cb-752 has a typical yield strength of 310 MPa (45 ksi) against 125 MPa (18.1 ksi) for Pure Nb — about 148% more. Tensile strength is 450 MPa (65.3 ksi) vs 220 MPa (31.9 ksi).

Which is cheaper, Cb-752 or Pure Nb?

Cb-752 is the lower-cost material: it sits in the high tier ($$$$) while Pure Nb is specialty ($$$$$). Part price depends far more on geometry, tolerance and quantity than on raw stock — upload a CAD file for a live quote.

Which welds better, Cb-752 or Pure Nb?

Pure Nb. Its weldability rates very good (80/100) against very good (70/100) for Cb-752.

Ready to make it?

Upload a CAD file and FabDigit prices the part in Cb-752 and Pure Nb 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.