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Refractory Metal ZIRLO vs Zr 702

Refractory Metal · grade comparison

Refractory Metal ZIRLO and Zr 702 are both refractory metal grades. ZIRLO is the stronger of the two: yield strength 530 MPa (76.9 ksi) against 290 MPa (42.1 ksi) for Zr 702, about 83% more; tensile strength follows at 650 MPa (94.3 ksi) vs 450 MPa (65.3 ksi). In exchange, Zr 702 is the more ductile: elongation 30% versus 16% for ZIRLO, and ZIRLO is harder (190 HB vs 150 HB). Zr 702 conducts heat better (22 W/m·K vs 14.5 W/m·K). On the shop floor, Zr 702 welds better (very good vs good).

ZIRLOChoose it when strength drives the design.

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

ZIRLO vs Zr 702: properties

ZIRLOZr 702

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Bulk Modulus

98 GPa14.2 Msi
92 GPa13.3 Msi

Poisson's Ratio

0.37
0.35

Tensile Strength (Ultimate)

650 MPa94.3 ksi
450 MPa65.3 ksi

Yield Strength (0.2% offset)

530 MPa76.9 ksi
290 MPa42.1 ksi

Elongation at Break

16%
30%

Reduction in Area

50%
45%

Compressive Strength

560 MPa81.2 ksi
300 MPa43.5 ksi

Shear Strength

390 MPa56.6 ksi
290 MPa42.1 ksi

Fatigue Strength (Endurance Limit)

250 MPa36.3 ksi
230 MPa33.4 ksi

Fracture Toughness (K_IC)

55 MPa·√m50.1 ksi·√in
65 MPa·√m59.2 ksi·√in

Charpy V-Notch Impact (RT)

45 J33.2 ft·lbf
60 J44.3 ft·lbf

Hardness, Brinell

190 HB
150 HB

Hardness, Rockwell B

93 HRB
85 HRB

Hardness, Rockwell C

14 HRC
—

Hardness, Vickers

205 HV
160 HV

Same in both: Elastic (Young's) Modulus 99 GPa14.4 Msi · Shear Modulus 36 GPa5.2 Msi

Physical

Density and transition temperatures.

Density

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

Melting Point (Solidus)

1,840°C3,344 °F
1,852°C3,366 °F

Liquidus Temperature

1,870°C3,398 °F
1,852°C3,366 °F

Thermal

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

Thermal Conductivity

14.5 W/m·K8.4 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

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

Max Service Temperature (continuous)

400°C752 °F
371°C700 °F

Same in both: Specific Heat Capacity 285 J/kg·K0.07 BTU/lb·°F · Min Service Temperature -196°C-321 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

2.4 % 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)

-0.25 V
-0.2 V

Same in both: Corrosion Resistance 92 / 100

Manufacturability

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

Machinability

32 / 100
35 / 100

Machinability Rating (AISI 1212 = 100 %)

22%
30%

Weldability

68 / 100
80 / 100

Formability (cold)

45 / 100
70 / 100

Polishability

60 / 100
70 / 100

Same in both: Castability 30 / 100 · Brazeability / Solderability 25 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

1,500 MJ/kg644,885 BTU/lb
1,250 MJ/kg537,404 BTU/lb

Embodied Carbon (primary production)

95 kg CO₂/kg
85 kg CO₂/kg

Embodied Water

700 L/kg83.9 gal/lb
900 L/kg108 gal/lb

Same in both: Typical Recycled Content 15%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

99 kN·m/kg
69 kN·m/kg

Specific Stiffness (E / density)

15.1 MN·m/kg
15.2 MN·m/kg

Modulus of Resilience

1,419 kJ/m³
425 kJ/m³

Thermal Diffusivity

7.8 mm²/s
11.9 mm²/s

Thermal Shock Resistance Index

16
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 702ZIRLO

Manufacturing and finishing

CapabilityZIRLOZr 702
Default condition——
Relative cost$$$$ High$$$$ High
Min. machined wall——
Best machined surface——

ZIRLO vs Zr 702 — frequently asked

Is ZIRLO stronger than Zr 702?

Yes. ZIRLO has a typical yield strength of 530 MPa (76.9 ksi) against 290 MPa (42.1 ksi) for Zr 702 — about 83% more. Tensile strength is 650 MPa (94.3 ksi) vs 450 MPa (65.3 ksi).

Which is cheaper, ZIRLO 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 welds better, ZIRLO or Zr 702?

Zr 702. Its weldability rates very good (80/100) against good (68/100) for ZIRLO.

Ready to make it?

Upload a CAD file and FabDigit prices the part in ZIRLO 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.