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Refractory Metal Zr 702 vs Zr 705C

Refractory Metal · grade comparison

Refractory Metal Zr 702 and Zr 705C are both refractory metal grades. Zr 705C is the stronger of the two: yield strength 386 MPa (56 ksi) against 290 MPa (42.1 ksi) for Zr 702, about 33% more; tensile strength follows at 495 MPa (71.8 ksi) vs 450 MPa (65.3 ksi). In exchange, Zr 702 is the more ductile: elongation 30% versus 13% for Zr 705C, and Zr 705C is harder (190 HB vs 150 HB). Zr 702 conducts heat better (22 W/m·K vs 17.1 W/m·K). On the shop floor, Zr 702 welds better (very good vs good).

Zr 702Choose it when the part is bent, formed or impact-loaded, or when it will be welded.

Zr 705CChoose it when strength drives the design.

Zr 702 vs Zr 705C: properties

Zr 702Zr 705C

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

99 GPa14.4 Msi
97 GPa14.1 Msi

Bulk Modulus

92 GPa13.3 Msi
95 GPa13.8 Msi

Tensile Strength (Ultimate)

450 MPa65.3 ksi
495 MPa71.8 ksi

Yield Strength (0.2% offset)

290 MPa42.1 ksi
386 MPa56 ksi

Elongation at Break

30%
13%

Reduction in Area

45%
24%

Compressive Strength

300 MPa43.5 ksi
400 MPa58 ksi

Shear Strength

290 MPa42.1 ksi
330 MPa47.9 ksi

Fatigue Strength (Endurance Limit)

230 MPa33.4 ksi
210 MPa30.5 ksi

Fracture Toughness (K_IC)

65 MPa·√m59.2 ksi·√in
40 MPa·√m36.4 ksi·√in

Charpy V-Notch Impact (RT)

60 J44.3 ft·lbf
14 J10.3 ft·lbf

Hardness, Brinell

150 HB
190 HB

Hardness, Rockwell B

85 HRB
92 HRB

Hardness, Vickers

160 HV
200 HV

Hardness, Rockwell C

—
13 HRC

Same in both: Shear Modulus 36 GPa5.2 Msi · Poisson's Ratio 0.35

Physical

Density and transition temperatures.

Density

6.51 g/cm³0.24 lb/in³
6.64 g/cm³0.24 lb/in³

Melting Point (Solidus)

1,852°C3,366 °F
1,840°C3,344 °F

Liquidus Temperature

1,852°C3,366 °F
1,860°C3,380 °F

Thermal

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

Thermal Conductivity

22 W/m·K12.7 BTU/hr·ft·°F
17.1 W/m·K9.9 BTU/hr·ft·°F

Specific Heat Capacity

285 J/kg·K0.07 BTU/lb·°F
281 J/kg·K0.07 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

5.9 µm/m·K3.3 µin/in·°F
6.3 µm/m·K3.5 µin/in·°F

Max Service Temperature (continuous)

371°C700 °F
375°C707 °F

Min Service Temperature

-196°C-321 °F
-50°C-58 °F

Same in both: Latent Heat of Fusion 153 J/g65.8 BTU/lb

Electrical

Conductivity and insulation.

Electrical Conductivity

4.3 % IACS
3.1 % IACS

Electrical Resistivity

4×10⁻⁷ Ω·m15.7 µΩ·in
5.5×10⁻⁷ Ω·m21.7 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.2 V
-0.25 V

Corrosion Resistance

92 / 100
90 / 100

Manufacturability

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

Machinability

35 / 100
30 / 100

Machinability Rating (AISI 1212 = 100 %)

30%
22%

Weldability

80 / 100
62 / 100

Formability (cold)

70 / 100
12 / 100

Castability

30 / 100
55 / 100

Same in both: Brazeability / Solderability 25 / 100 · Polishability 70 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

1,250 MJ/kg537,404 BTU/lb
1,600 MJ/kg687,877 BTU/lb

Embodied Carbon (primary production)

85 kg CO₂/kg
105 kg CO₂/kg

Embodied Water

900 L/kg108 gal/lb
600 L/kg71.9 gal/lb

Typical Recycled Content

15%
25%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

69 kN·m/kg
75 kN·m/kg

Specific Stiffness (E / density)

15.2 MN·m/kg
14.6 MN·m/kg

Modulus of Resilience

425 kJ/m³
768 kJ/m³

Thermal Diffusivity

11.9 mm²/s
9.2 mm²/s

Thermal Shock Resistance Index

17
14

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 scaleZr 702Zr 705C

Manufacturing and finishing

CapabilityZr 702Zr 705C
Default condition——
Relative cost$$$$ High$$$$ High
Min. machined wall——
Best machined surface——

Zr 702 vs Zr 705C — frequently asked

Is Zr 705C stronger than Zr 702?

Yes. Zr 705C has a typical yield strength of 386 MPa (56 ksi) against 290 MPa (42.1 ksi) for Zr 702 — about 33% more. Tensile strength is 495 MPa (71.8 ksi) vs 450 MPa (65.3 ksi).

Which is cheaper, Zr 702 or Zr 705C?

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 is easier to machine, Zr 702 or Zr 705C?

Zr 702. Its machinability rates fair (35/100) against poor (30/100) for Zr 705C; for welding the order is Zr 702 first (very good, 80/100) then Zr 705C (good, 62/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in Zr 702 and Zr 705C 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.