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Cobalt-Chrome Alloy Haynes 188 vs S-816

Cobalt-Chrome Alloy · grade comparison

Cobalt-Chrome Alloy Haynes 188 and S-816 are both cobalt-chrome alloy grades. Both yield at about 464 MPa — strength does not separate them. Haynes 188 is the more ductile: elongation 53% versus 18% for S-816, and S-816 is harder (300 HB vs 215 HB). S-816 is lighter (8.68 g/cm³ vs 8.98 g/cm³ for Haynes 188) and Haynes 188 is stiffer (232 GPa vs 200 GPa). On the shop floor, Haynes 188 welds better (very good vs poor).

Haynes 188Choose it when the part is bent, formed or impact-loaded, or when the part sees heat.

S-816Choose it when weight is the constraint.

Haynes 188 vs S-816: properties

Haynes 188S-816

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

232 GPa33.6 Msi
200 GPa29 Msi

Shear Modulus

89 GPa12.9 Msi
77 GPa11.2 Msi

Bulk Modulus

193 GPa28 Msi
172 GPa24.9 Msi

Tensile Strength (Ultimate)

960 MPa139 ksi
1,000 MPa145 ksi

Yield Strength (0.2% offset)

464 MPa67.3 ksi
480 MPa69.6 ksi

Elongation at Break

53%
18%

Reduction in Area

50%
20%

Shear Strength

620 MPa89.9 ksi
640 MPa92.8 ksi

Fatigue Strength (Endurance Limit)

380 MPa55.1 ksi
290 MPa42.1 ksi

Charpy V-Notch Impact (RT)

110 J81.1 ft·lbf
22 J16.2 ft·lbf

Hardness, Brinell

215 HB
300 HB

Hardness, Rockwell B

95 HRB
—

Hardness, Vickers

225 HV
315 HV

Hardness, Rockwell C

—
31 HRC

Same in both: Poisson's Ratio 0.3

Physical

Density and transition temperatures.

Density

8.98 g/cm³0.32 lb/in³
8.68 g/cm³0.31 lb/in³

Melting Point (Solidus)

1,302°C2,376 °F
1,330°C2,426 °F

Liquidus Temperature

1,330°C2,426 °F
1,400°C2,552 °F

Thermal

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

Thermal Conductivity

10.8 W/m·K6.2 BTU/hr·ft·°F
12.5 W/m·K7.2 BTU/hr·ft·°F

Specific Heat Capacity

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

Thermal Expansion (CTE, 20–100 °C)

11.9 µm/m·K6.6 µin/in·°F
13.9 µm/m·K7.7 µin/in·°F

Max Service Temperature (continuous)

1,095°C2,003 °F
870°C1,598 °F

Latent Heat of Fusion

—
270 J/g116 BTU/lb

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

Electrical

Conductivity and insulation.

Electrical Conductivity

1.7 % IACS
1.9 % IACS

Electrical Resistivity

1.01×10⁻⁶ Ω·m39.8 µΩ·in
9.1×10⁻⁷ Ω·m35.8 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

78 / 100
74 / 100

Same in both: Galvanic Potential (seawater, vs SCE) -0.15 V

Manufacturability

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

Machinability

15 / 100
13 / 100

Machinability Rating (AISI 1212 = 100 %)

12%
10%

Weldability

75 / 100
25 / 100

Formability (cold)

65 / 100
15 / 100

Castability

35 / 100
68 / 100

Brazeability / Solderability

60 / 100
55 / 100

Polishability

70 / 100
65 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

280 MJ/kg120,378 BTU/lb
190 MJ/kg81,685 BTU/lb

Embodied Carbon (primary production)

19 kg CO₂/kg
13 kg CO₂/kg

Embodied Water

500 L/kg59.9 gal/lb
340 L/kg40.7 gal/lb

Same in both: Typical Recycled Content 30%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

107 kN·m/kg
115 kN·m/kg

Specific Stiffness (E / density)

25.8 MN·m/kg
23 MN·m/kg

Modulus of Resilience

464 kJ/m³
576 kJ/m³

Thermal Diffusivity

3 mm²/s
3.4 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 scaleHaynes 188S-816

Manufacturing and finishing

CapabilityHaynes 188S-816
Default condition——
Relative cost$$$$ High$$$$ High
Min. machined wall——
Best machined surface——

Haynes 188 vs S-816 — frequently asked

What is the difference between Haynes 188 and S-816?

Cobalt-Chrome Alloy Haynes 188 and S-816 are both cobalt-chrome alloy grades. Both yield at about 464 MPa — strength does not separate them. Haynes 188 is the more ductile: elongation 53% versus 18% for S-816, and S-816 is harder (300 HB vs 215 HB).

Which is cheaper, Haynes 188 or S-816?

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, Haynes 188 or S-816?

Haynes 188. Its weldability rates very good (75/100) against poor (25/100) for S-816.

Ready to make it?

Upload a CAD file and FabDigit prices the part in Haynes 188 and S-816 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.