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Cobalt-Chrome Alloy S-816 vs Stellite 6

Cobalt-Chrome Alloy · grade comparison

Cobalt-Chrome Alloy S-816 and Stellite 6 are both cobalt-chrome alloy grades. Stellite 6 is the stronger of the two: yield strength 541 MPa (78.5 ksi) against 480 MPa (69.6 ksi) for S-816, about 13% more. In exchange, S-816 is the more ductile: elongation 18% versus 1% for Stellite 6, and Stellite 6 is harder (40 HRC vs 31 HRC). Stellite 6 is stiffer (220 GPa vs 200 GPa) and S-816 runs hotter in service (870°C vs 800°C continuous). On the shop floor, Stellite 6 welds better (good vs poor) and S-816 sits in a lower cost tier (high, $$$$) than Stellite 6 (specialty, $$$$$).

S-816Choose it when the part is bent, formed or impact-loaded, or when the part sees heat.

Stellite 6Choose it when strength drives the design, or when it will be welded.

S-816 vs Stellite 6: properties

S-816Stellite 6

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

200 GPa29 Msi
220 GPa31.9 Msi

Shear Modulus

77 GPa11.2 Msi
85 GPa12.3 Msi

Bulk Modulus

172 GPa24.9 Msi
180 GPa26.1 Msi

Tensile Strength (Ultimate)

1,000 MPa145 ksi
834 MPa121 ksi

Yield Strength (0.2% offset)

480 MPa69.6 ksi
541 MPa78.5 ksi

Elongation at Break

18%
1%

Reduction in Area

20%
—

Shear Strength

640 MPa92.8 ksi
—

Fatigue Strength (Endurance Limit)

290 MPa42.1 ksi
275 MPa39.9 ksi

Charpy V-Notch Impact (RT)

22 J16.2 ft·lbf
5 J3.7 ft·lbf

Hardness, Brinell

300 HB
—

Hardness, Rockwell C

31 HRC
40 HRC

Hardness, Vickers

315 HV
425 HV

Compressive Strength

—
1,450 MPa210 ksi

Fracture Toughness (K_IC)

—
25 MPa·√m22.8 ksi·√in

Same in both: Poisson's Ratio 0.3

Physical

Density and transition temperatures.

Density

8.68 g/cm³0.31 lb/in³
8.44 g/cm³0.3 lb/in³

Melting Point (Solidus)

1,330°C2,426 °F
1,285°C2,345 °F

Liquidus Temperature

1,400°C2,552 °F
1,395°C2,543 °F

Thermal

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

Thermal Conductivity

12.5 W/m·K7.2 BTU/hr·ft·°F
14.8 W/m·K8.6 BTU/hr·ft·°F

Specific Heat Capacity

420 J/kg·K0.1 BTU/lb·°F
423 J/kg·K0.1 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

13.9 µm/m·K7.7 µin/in·°F
12.5 µm/m·K6.9 µin/in·°F

Latent Heat of Fusion

270 J/g116 BTU/lb
—

Max Service Temperature (continuous)

870°C1,598 °F
800°C1,472 °F

Same in both: Min Service Temperature -196°C-321 °F

Electrical

Conductivity and insulation.

Electrical Resistivity

9.1×10⁻⁷ Ω·m35.8 µΩ·in
9×10⁻⁷ Ω·m35.4 µΩ·in

Same in both: Electrical Conductivity 1.9 % IACS

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.15 V
-0.25 V

Corrosion Resistance

74 / 100
70 / 100

Manufacturability

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

Machinability

13 / 100
8 / 100

Machinability Rating (AISI 1212 = 100 %)

10%
5%

Weldability

25 / 100
55 / 100

Formability (cold)

15 / 100
5 / 100

Castability

68 / 100
70 / 100

Polishability

65 / 100
85 / 100

Same in both: Brazeability / Solderability 55 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

190 MJ/kg81,685 BTU/lb
150 MJ/kg64,488 BTU/lb

Embodied Water

340 L/kg40.7 gal/lb
400 L/kg47.9 gal/lb

Same in both: Embodied Carbon (primary production) 13 kg CO₂/kg · Typical Recycled Content 30%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

115 kN·m/kg
99 kN·m/kg

Specific Stiffness (E / density)

23 MN·m/kg
26.1 MN·m/kg

Modulus of Resilience

576 kJ/m³
665 kJ/m³

Thermal Diffusivity

3.4 mm²/s
4.1 mm²/s

Same in both: Thermal Shock Resistance Index 4

Strength versus weight

Yield strength against density for every cobalt-chrome alloy grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.

5007001,0001,5002,0008.28.48.68.89Density (g/cm³)Yield strength (MPa) — log scaleStellite 6S-816

Manufacturing and finishing

CapabilityS-816Stellite 6
Default condition—As Cast
Relative cost$$$$ High$$$$$ Specialty
Min. machined wall——
Best machined surface——

S-816 vs Stellite 6 — frequently asked

Is Stellite 6 stronger than S-816?

Yes. Stellite 6 has a typical yield strength of 541 MPa (78.5 ksi) against 480 MPa (69.6 ksi) for S-816 — about 13% more. Tensile strength is 834 MPa (121 ksi) vs 1,000 MPa (145 ksi).

Which is cheaper, S-816 or Stellite 6?

S-816 is the lower-cost material: it sits in the high tier ($$$$) while Stellite 6 is specialty ($$$$$). Part price depends far more on geometry, tolerance and quantity than on raw stock — upload a CAD file for a live quote.

Which is easier to machine, S-816 or Stellite 6?

S-816, by a small margin. Both rate not recommended for machinability — 13/100 against 8/100 for Stellite 6; for welding the order is Stellite 6 first (good, 55/100) then S-816 (poor, 25/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in S-816 and Stellite 6 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.