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Refractory Metal Zircaloy-4 vs Zr 702

Refractory Metal · grade comparison

Refractory Metal Zircaloy-4 and Zr 702 are both refractory metal grades. Zircaloy-4 is the stronger of the two: yield strength 330 MPa (47.9 ksi) against 290 MPa (42.1 ksi) for Zr 702, about 14% more; tensile strength follows at 480 MPa (69.6 ksi) vs 450 MPa (65.3 ksi). Zircaloy-4 is harder — 180 HV against 160 HV for Zr 702 — which matters for wear surfaces and threads. Zr 702 conducts heat better (22 W/m·K vs 13 W/m·K).

Zircaloy-4Choose it when strength drives the design, or when surface hardness matters.

Zircaloy-4 vs Zr 702: properties

Zircaloy-4Zr 702

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Bulk Modulus

100 GPa14.5 Msi
92 GPa13.3 Msi

Tensile Strength (Ultimate)

480 MPa69.6 ksi
450 MPa65.3 ksi

Yield Strength (0.2% offset)

330 MPa47.9 ksi
290 MPa42.1 ksi

Elongation at Break

28%
30%

Compressive Strength

350 MPa50.8 ksi
300 MPa43.5 ksi

Shear Strength

300 MPa43.5 ksi
290 MPa42.1 ksi

Fatigue Strength (Endurance Limit)

240 MPa34.8 ksi
230 MPa33.4 ksi

Fracture Toughness (K_IC)

70 MPa·√m63.7 ksi·√in
65 MPa·√m59.2 ksi·√in

Charpy V-Notch Impact (RT)

65 J47.9 ft·lbf
60 J44.3 ft·lbf

Hardness, Rockwell B

89 HRB
85 HRB

Hardness, Vickers

180 HV
160 HV

Hardness, Brinell

—
150 HB

Same in both: Elastic (Young's) Modulus 99 GPa14.4 Msi · Shear Modulus 36 GPa5.2 Msi · Poisson's Ratio 0.35 · Reduction in Area 45%

Physical

Density and transition temperatures.

Density

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

Melting Point (Solidus)

1,760°C3,200 °F
1,852°C3,366 °F

Liquidus Temperature

1,850°C3,362 °F
1,852°C3,366 °F

Thermal

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

Thermal Conductivity

13 W/m·K7.5 BTU/hr·ft·°F
22 W/m·K12.7 BTU/hr·ft·°F

Thermal Expansion (CTE, 20–100 °C)

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

Latent Heat of Fusion

225 J/g96.7 BTU/lb
153 J/g65.8 BTU/lb

Max Service Temperature (continuous)

400°C752 °F
371°C700 °F

Min Service Temperature

-200°C-328 °F
-196°C-321 °F

Same in both: Specific Heat Capacity 285 J/kg·K0.07 BTU/lb·°F

Electrical

Conductivity and insulation.

Electrical Conductivity

2.5 % IACS
4.3 % IACS

Electrical Resistivity

7×10⁻⁷ Ω·m27.6 µΩ·in
4×10⁻⁷ Ω·m15.7 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.1 V
-0.2 V

Corrosion Resistance

88 / 100
92 / 100

Manufacturability

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

Machinability

30 / 100
35 / 100

Machinability Rating (AISI 1212 = 100 %)

22%
30%

Weldability

72 / 100
80 / 100

Castability

20 / 100
30 / 100

Polishability

60 / 100
70 / 100

Same in both: Formability (cold) 70 / 100 · Brazeability / Solderability 25 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

1,400 MJ/kg601,892 BTU/lb
1,250 MJ/kg537,404 BTU/lb

Embodied Carbon (primary production)

90 kg CO₂/kg
85 kg CO₂/kg

Embodied Water

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

Typical Recycled Content

10%
15%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

73 kN·m/kg
69 kN·m/kg

Specific Stiffness (E / density)

15.1 MN·m/kg
15.2 MN·m/kg

Modulus of Resilience

550 kJ/m³
425 kJ/m³

Thermal Diffusivity

7 mm²/s
11.9 mm²/s

Thermal Shock Resistance Index

11
17

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 702Zircaloy-4

Manufacturing and finishing

CapabilityZircaloy-4Zr 702
Default condition——
Relative cost$$$$ High$$$$ High
Min. machined wall——
Best machined surface——

Zircaloy-4 vs Zr 702 — frequently asked

Is Zircaloy-4 stronger than Zr 702?

Yes. Zircaloy-4 has a typical yield strength of 330 MPa (47.9 ksi) against 290 MPa (42.1 ksi) for Zr 702 — about 14% more. Tensile strength is 480 MPa (69.6 ksi) vs 450 MPa (65.3 ksi).

Which is cheaper, Zircaloy-4 or Zr 702?

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, Zircaloy-4 or Zr 702?

Zr 702. Its machinability rates fair (35/100) against poor (30/100) for Zircaloy-4; for welding the order is Zr 702 first (very good, 80/100) then Zircaloy-4 (very good, 72/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in Zircaloy-4 and Zr 702 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.