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Refractory Metal Zr 702C vs Zr 705C

Refractory Metal · grade comparison

Refractory Metal Zr 702C and Zr 705C are both refractory metal grades. Zr 705C is the stronger of the two: yield strength 386 MPa (56 ksi) against 250 MPa (36.3 ksi) for Zr 702C, about 54% more; tensile strength follows at 495 MPa (71.8 ksi) vs 450 MPa (65.3 ksi). In exchange, Zr 702C is the more ductile: elongation 16% versus 13% for Zr 705C, and Zr 705C is harder (190 HB vs 150 HB). Zr 702C conducts heat better (22 W/m·K vs 17.1 W/m·K). On the shop floor, Zr 702C welds better (very good vs good).

Zr 702CChoose 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 702C vs Zr 705C: properties

Zr 702CZr 705C

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

99 GPa14.4 Msi
97 GPa14.1 Msi

Bulk Modulus

90 GPa13.1 Msi
95 GPa13.8 Msi

Poisson's Ratio

0.34
0.35

Tensile Strength (Ultimate)

450 MPa65.3 ksi
495 MPa71.8 ksi

Yield Strength (0.2% offset)

250 MPa36.3 ksi
386 MPa56 ksi

Elongation at Break

16%
13%

Reduction in Area

25%
24%

Shear Strength

290 MPa42.1 ksi
330 MPa47.9 ksi

Fatigue Strength (Endurance Limit)

160 MPa23.2 ksi
210 MPa30.5 ksi

Fracture Toughness (K_IC)

55 MPa·√m50.1 ksi·√in
40 MPa·√m36.4 ksi·√in

Charpy V-Notch Impact (RT)

25 J18.4 ft·lbf
14 J10.3 ft·lbf

Hardness, Brinell

150 HB
190 HB

Hardness, Rockwell B

88 HRB
92 HRB

Compressive Strength

—
400 MPa58 ksi

Hardness, Rockwell C

—
13 HRC

Hardness, Vickers

—
200 HV

Same in both: Shear Modulus 36 GPa5.2 Msi

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

1,855°C3,371 °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

Latent Heat of Fusion

155 J/g66.6 BTU/lb
153 J/g65.8 BTU/lb

Max Service Temperature (continuous)

400°C752 °F
375°C707 °F

Min Service Temperature

-196°C-321 °F
-50°C-58 °F

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).

Corrosion Resistance

92 / 100
90 / 100

Same in both: Galvanic Potential (seawater, vs SCE) -0.25 V

Manufacturability

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

Machinability

35 / 100
30 / 100

Machinability Rating (AISI 1212 = 100 %)

32%
22%

Weldability

75 / 100
62 / 100

Formability (cold)

20 / 100
12 / 100

Polishability

65 / 100
70 / 100

Same in both: Castability 55 / 100 · Brazeability / Solderability 25 / 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)

80 kg CO₂/kg
105 kg CO₂/kg

Same in both: Embodied Water 600 L/kg71.9 gal/lb · Typical Recycled Content 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

316 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 702CZr 705C

Manufacturing and finishing

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

Zr 702C vs Zr 705C — frequently asked

Is Zr 705C stronger than Zr 702C?

Yes. Zr 705C has a typical yield strength of 386 MPa (56 ksi) against 250 MPa (36.3 ksi) for Zr 702C — about 54% more. Tensile strength is 495 MPa (71.8 ksi) vs 450 MPa (65.3 ksi).

Which is cheaper, Zr 702C 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 702C or Zr 705C?

Zr 702C. Its machinability rates fair (35/100) against poor (30/100) for Zr 705C; for welding the order is Zr 702C first (very good, 75/100) then Zr 705C (good, 62/100).

Ready to make it?

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