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OK8/BK8 vs YG6

Ceramic · grade comparison

OK8/BK8 and YG6 are both ceramic grades. OK8/BK8 is the stronger of the two: tensile strength 1,200 MPa (174 ksi) against 1,100 MPa (160 ksi) for YG6, about 9% more. In exchange, YG6 is the more ductile: elongation 0.2% versus 0% for OK8/BK8, and YG6 is harder (1,580 HV vs 1,450 HV). OK8/BK8 runs hotter in service (800°C vs 600°C continuous).

OK8/BK8Choose it when strength drives the design, or when the part sees heat.

YG6Choose it when the part is bent, formed or impact-loaded.

OK8/BK8 vs YG6: properties

OK8/BK8YG6

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

600 GPa87 Msi
630 GPa91.4 Msi

Shear Modulus

245 GPa35.5 Msi
255 GPa37 Msi

Bulk Modulus

370 GPa53.7 Msi
375 GPa54.4 Msi

Tensile Strength (Ultimate)

1,200 MPa174 ksi
1,100 MPa160 ksi

Elongation at Break

0%
0.2%

Compressive Strength

4,400 MPa638 ksi
4,600 MPa667 ksi

Flexural Strength

1,900 MPa276 ksi
1,800 MPa261 ksi

Shear Strength

1,100 MPa160 ksi
1,200 MPa174 ksi

Fracture Toughness (K_IC)

14.5 MPa·√m13.2 ksi·√in
10 MPa·√m9.1 ksi·√in

Hardness, Vickers

1,450 HV
1,580 HV

Hardness, Knoop

1,400 HK
1,500 HK

Same in both: Poisson's Ratio 0.22 · Hardness, Mohs 9

Physical

Density and transition temperatures.

Density

14.6 g/cm³0.53 lb/in³
14.9 g/cm³0.54 lb/in³

Same in both: Melting Point (Solidus) 1,320°C2,408 °F · Porosity 0.02%

Thermal

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

Thermal Conductivity

75 W/m·K43.3 BTU/hr·ft·°F
80 W/m·K46.2 BTU/hr·ft·°F

Thermal Expansion (CTE, 20–100 °C)

5.2 µm/m·K2.9 µin/in·°F
4.5 µm/m·K2.5 µin/in·°F

Max Service Temperature (continuous)

800°C1,472 °F
600°C1,112 °F

Same in both: Specific Heat Capacity 220 J/kg·K0.05 BTU/lb·°F · Min Service Temperature -196°C-321 °F

Electrical

Conductivity and insulation.

Same in both: Electrical Resistivity 2×10⁻⁷ Ω·m7.87 µΩ·in · Volume Resistivity 2×10⁻⁵ Ω·cm

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

45 / 100
55 / 100

Manufacturability

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

Machinability

4 / 100
5 / 100

Polishability

92 / 100
90 / 100

Same in both: Sintering / Firing Temperature 1,420°C2,588 °F

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

420 MJ/kg180,568 BTU/lb
330 MJ/kg141,875 BTU/lb

Embodied Carbon (primary production)

30 kg CO₂/kg
24 kg CO₂/kg

Same in both: Embodied Water 400 L/kg47.9 gal/lb · Typical Recycled Content 30%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

82 kN·m/kg
74 kN·m/kg

Specific Stiffness (E / density)

41.1 MN·m/kg
42.3 MN·m/kg

Thermal Diffusivity

23.3 mm²/s
24.4 mm²/s

Thermal Shock Resistance Index

29
31

Strength versus weight

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

501002005001,000234567Density (g/cm³)Yield strength (MPa) — log scale

Manufacturing and finishing

CapabilityOK8/BK8YG6
Default condition——
Relative cost$$$$ High$$$$ High
Min. machined wall——
Best machined surface——

OK8/BK8 vs YG6 — frequently asked

Is OK8/BK8 stronger than YG6?

Yes. OK8/BK8 has a typical tensile strength of 1,200 MPa (174 ksi) against 1,100 MPa (160 ksi) for YG6 — about 9% more.

Which is cheaper, OK8/BK8 or YG6?

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.

When should I choose OK8/BK8 over YG6?

Pick OK8/BK8 when strength drives the design, or when the part sees heat. Pick YG6 when the part is bent, formed or impact-loaded.

Ready to make it?

Upload a CAD file and FabDigit prices the part in OK8/BK8 and YG6 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.