FabDigitFabDigit

Refractory Metal O-30H vs S-65

Refractory Metal · grade comparison

Refractory Metal O-30H and S-65 are both refractory metal grades. S-65 is the stronger of the two: yield strength 230 MPa (33.4 ksi) against 207 MPa (30 ksi) for O-30H, about 11% more; tensile strength follows at 350 MPa (50.8 ksi) vs 324 MPa (47 ksi). S-65 is the more ductile: elongation 4.5% versus 3% for O-30H, and O-30H is harder (140 HB vs 115 HB). On the shop floor, S-65 machines more easily (45 vs 35 out of 100).

S-65Choose it when strength drives the design, or when the part is bent, formed or impact-loaded.

O-30H vs S-65: properties

O-30HS-65

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Shear Modulus

145 GPa21 Msi
142 GPa20.6 Msi

Bulk Modulus

116 GPa16.8 Msi
117 GPa17 Msi

Poisson's Ratio

0.08
0.07

Tensile Strength (Ultimate)

324 MPa47 ksi
350 MPa50.8 ksi

Yield Strength (0.2% offset)

207 MPa30 ksi
230 MPa33.4 ksi

Elongation at Break

3%
4.5%

Reduction in Area

4%
—

Compressive Strength

480 MPa69.6 ksi
—

Shear Strength

195 MPa28.3 ksi
205 MPa29.7 ksi

Fatigue Strength (Endurance Limit)

110 MPa16 ksi
190 MPa27.6 ksi

Fracture Toughness (K_IC)

11 MPa·√m10 ksi·√in
13 MPa·√m11.8 ksi·√in

Charpy V-Notch Impact (RT)

2 J1.1 ft·lbf
—

Hardness, Brinell

140 HB
115 HB

Hardness, Rockwell B

82 HRB
78 HRB

Hardness, Vickers

150 HV
145 HV

Same in both: Elastic (Young's) Modulus 303 GPa43.9 Msi

Physical

Density and transition temperatures.

Same in both: Density 1.85 g/cm³0.07 lb/in³ · Melting Point (Solidus) 1,287°C2,349 °F · Liquidus Temperature 1,289°C2,352 °F

Thermal

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

Thermal Conductivity

216 W/m·K125 BTU/hr·ft·°F
210 W/m·K121 BTU/hr·ft·°F

Min Service Temperature

-269°C-452 °F
-196°C-321 °F

Same in both: Specific Heat Capacity 1,925 J/kg·K0.46 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 11.3 µm/m·K6.3 µin/in·°F · Latent Heat of Fusion 1,355 J/g583 BTU/lb · Max Service Temperature (continuous) 500°C932 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

42 % IACS
40 % IACS

Electrical Resistivity

4.1×10⁻⁸ Ω·m1.61 µΩ·in
4.3×10⁻⁸ Ω·m1.69 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

42 / 100
45 / 100

Same in both: Galvanic Potential (seawater, vs SCE) -1 V

Manufacturability

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

Machinability

35 / 100
45 / 100

Weldability

15 / 100
20 / 100

Formability (cold)

10 / 100
15 / 100

Polishability

78 / 100
65 / 100

Castability

—
10 / 100

Same in both: Machinability Rating (AISI 1212 = 100 %) 40% · Brazeability / Solderability 55 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

1,500 MJ/kg644,885 BTU/lb
4,000 MJ/kg1,719,692 BTU/lb

Embodied Carbon (primary production)

95 kg CO₂/kg
250 kg CO₂/kg

Embodied Water

1,500 L/kg180 gal/lb
2,500 L/kg300 gal/lb

Typical Recycled Content

10%
15%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

175 kN·m/kg
189 kN·m/kg

Modulus of Resilience

71 kJ/m³
87 kJ/m³

Thermal Diffusivity

60.7 mm²/s
59 mm²/s

Thermal Shock Resistance Index

20
21

Same in both: Specific Stiffness (E / density) 163.8 MN·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 scaleS-65O-30H

Manufacturing and finishing

CapabilityO-30HS-65
Default condition——
Relative cost$$$$ High$$$$ High
Min. machined wall——
Best machined surface——

O-30H vs S-65 — frequently asked

Is S-65 stronger than O-30H?

Yes. S-65 has a typical yield strength of 230 MPa (33.4 ksi) against 207 MPa (30 ksi) for O-30H — about 11% more. Tensile strength is 350 MPa (50.8 ksi) vs 324 MPa (47 ksi).

Which is cheaper, O-30H or S-65?

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, O-30H or S-65?

S-65, by a small margin. Both rate fair for machinability — 45/100 against 35/100 for O-30H; for welding the order is S-65 first (poor, 20/100) then O-30H (poor, 15/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in O-30H and S-65 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.