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Refractory Metal E635 vs Zr 704C

Refractory Metal · grade comparison

Refractory Metal E635 and Zr 704C are both refractory metal grades. E635 is the stronger of the two: yield strength 340 MPa (49.3 ksi) against 300 MPa (43.5 ksi) for Zr 704C, about 13% more. E635 is the more ductile: elongation 22% versus 13% for Zr 704C. E635 conducts heat better (14.5 W/m·K vs 13 W/m·K).

E635Choose it when strength drives the design, or when the part is bent, formed or impact-loaded.

E635 vs Zr 704C: properties

E635Zr 704C

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

97 GPa14.1 Msi
99 GPa14.4 Msi

Bulk Modulus

100 GPa14.5 Msi
97 GPa14.1 Msi

Poisson's Ratio

0.35
0.34

Tensile Strength (Ultimate)

470 MPa68.2 ksi
450 MPa65.3 ksi

Yield Strength (0.2% offset)

340 MPa49.3 ksi
300 MPa43.5 ksi

Elongation at Break

22%
13%

Reduction in Area

48%
20%

Compressive Strength

350 MPa50.8 ksi
320 MPa46.4 ksi

Shear Strength

290 MPa42.1 ksi
300 MPa43.5 ksi

Fatigue Strength (Endurance Limit)

240 MPa34.8 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)

30 J22.1 ft·lbf
20 J14.8 ft·lbf

Hardness, Brinell

185 HB
190 HB

Hardness, Vickers

195 HV
200 HV

Same in both: Shear Modulus 36 GPa5.2 Msi · Hardness, Rockwell B 89 HRB

Physical

Density and transition temperatures.

Density

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

Melting Point (Solidus)

1,760°C3,200 °F
1,800°C3,272 °F

Liquidus Temperature

1,830°C3,326 °F
1,845°C3,353 °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
13 W/m·K7.5 BTU/hr·ft·°F

Latent Heat of Fusion

235 J/g101 BTU/lb
155 J/g66.6 BTU/lb

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 · Thermal Expansion (CTE, 20–100 °C) 6 µm/m·K3.3 µin/in·°F · Max Service Temperature (continuous) 400°C752 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

2.6 % IACS
2.5 % IACS

Electrical Resistivity

6.7×10⁻⁷ Ω·m26.4 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)

-0.3 V
-0.15 V

Corrosion Resistance

86 / 100
90 / 100

Manufacturability

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

Machinability Rating (AISI 1212 = 100 %)

25%
28%

Weldability

70 / 100
65 / 100

Formability (cold)

60 / 100
20 / 100

Castability

20 / 100
55 / 100

Brazeability / Solderability

25 / 100
20 / 100

Same in both: Machinability 30 / 100 · Polishability 60 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

1,400 MJ/kg601,892 BTU/lb
1,200 MJ/kg515,908 BTU/lb

Embodied Carbon (primary production)

90 kg CO₂/kg
75 kg CO₂/kg

Embodied Water

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

Typical Recycled Content

10%
25%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

72 kN·m/kg
69 kN·m/kg

Specific Stiffness (E / density)

14.8 MN·m/kg
15.1 MN·m/kg

Modulus of Resilience

596 kJ/m³
455 kJ/m³

Thermal Diffusivity

7.7 mm²/s
7 mm²/s

Thermal Shock Resistance Index

12
10

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 704CE635

Manufacturing and finishing

CapabilityE635Zr 704C
Default condition——
Relative cost$$$$ High$$$$ High
Min. machined wall——
Best machined surface——

E635 vs Zr 704C — frequently asked

Is E635 stronger than Zr 704C?

Yes. E635 has a typical yield strength of 340 MPa (49.3 ksi) against 300 MPa (43.5 ksi) for Zr 704C — about 13% more. Tensile strength is 470 MPa (68.2 ksi) vs 450 MPa (65.3 ksi).

Which is cheaper, E635 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 welds better, E635 or Zr 704C?

E635. Its weldability rates very good (70/100) against good (65/100) for Zr 704C.

Ready to make it?

Upload a CAD file and FabDigit prices the part in E635 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.