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Refractory Metal Zr 702C vs Zr 704C

Refractory Metal · grade comparison

Refractory Metal Zr 702C and Zr 704C are both refractory metal grades. Zr 704C is the stronger of the two: yield strength 300 MPa (43.5 ksi) against 250 MPa (36.3 ksi) for Zr 702C, about 20% more. In exchange, Zr 702C is the more ductile: elongation 16% versus 13% for Zr 704C, and Zr 704C is harder (190 HB vs 150 HB). Zr 702C conducts heat better (22 W/m·K vs 13 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 704CChoose it when strength drives the design.

Zr 702C vs Zr 704C: properties

Zr 702CZr 704C

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Bulk Modulus

90 GPa13.1 Msi
97 GPa14.1 Msi

Yield Strength (0.2% offset)

250 MPa36.3 ksi
300 MPa43.5 ksi

Elongation at Break

16%
13%

Reduction in Area

25%
20%

Shear Strength

290 MPa42.1 ksi
300 MPa43.5 ksi

Fatigue Strength (Endurance Limit)

160 MPa23.2 ksi
200 MPa29 ksi

Fracture Toughness (K_IC)

55 MPa·√m50.1 ksi·√in
50 MPa·√m45.5 ksi·√in

Charpy V-Notch Impact (RT)

25 J18.4 ft·lbf
20 J14.8 ft·lbf

Hardness, Brinell

150 HB
190 HB

Hardness, Rockwell B

88 HRB
89 HRB

Compressive Strength

—
320 MPa46.4 ksi

Hardness, Vickers

—
200 HV

Same in both: Elastic (Young's) Modulus 99 GPa14.4 Msi · Shear Modulus 36 GPa5.2 Msi · Poisson's Ratio 0.34 · Tensile Strength (Ultimate) 450 MPa65.3 ksi

Physical

Density and transition temperatures.

Density

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

Melting Point (Solidus)

1,852°C3,366 °F
1,800°C3,272 °F

Liquidus Temperature

1,855°C3,371 °F
1,845°C3,353 °F

Thermal

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

Thermal Conductivity

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

Thermal Expansion (CTE, 20–100 °C)

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

Min Service Temperature

-196°C-321 °F
-75°C-103 °F

Same in both: Specific Heat Capacity 285 J/kg·K0.07 BTU/lb·°F · Latent Heat of Fusion 155 J/g66.6 BTU/lb · Max Service Temperature (continuous) 400°C752 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

4.3 % IACS
2.5 % IACS

Electrical Resistivity

4×10⁻⁷ Ω·m15.7 µΩ·in
6.8×10⁻⁷ Ω·m26.8 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.25 V
-0.15 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 %)

32%
28%

Weldability

75 / 100
65 / 100

Brazeability / Solderability

25 / 100
20 / 100

Polishability

65 / 100
60 / 100

Same in both: Formability (cold) 20 / 100 · Castability 55 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

1,250 MJ/kg537,404 BTU/lb
1,200 MJ/kg515,908 BTU/lb

Embodied Carbon (primary production)

80 kg CO₂/kg
75 kg CO₂/kg

Embodied Water

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

Same in both: Typical Recycled Content 25%

Common Calculations

Ratios derived from the values above.

Specific Stiffness (E / density)

15.2 MN·m/kg
15.1 MN·m/kg

Modulus of Resilience

316 kJ/m³
455 kJ/m³

Thermal Diffusivity

11.9 mm²/s
7 mm²/s

Thermal Shock Resistance Index

17
10

Same in both: Specific Strength (UTS / density) 69 kN·m/kg

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 704C

Manufacturing and finishing

CapabilityZr 702CZr 704C
Default condition——
Relative cost$$$$ High$$$$ High
Min. machined wall——
Best machined surface——

Zr 702C vs Zr 704C — frequently asked

Is Zr 704C stronger than Zr 702C?

Yes. Zr 704C has a typical yield strength of 300 MPa (43.5 ksi) against 250 MPa (36.3 ksi) for Zr 702C — about 20% more. Tensile strength is 450 MPa (65.3 ksi) vs 450 MPa (65.3 ksi).

Which is cheaper, Zr 702C or Zr 704C?

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 704C?

Zr 702C. Its machinability rates fair (35/100) against poor (30/100) for Zr 704C; for welding the order is Zr 702C first (very good, 75/100) then Zr 704C (good, 65/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in Zr 702C and Zr 704C 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.