OK6/BK6
GOST OK6/BK6 (ОК6/БК6) · GB YG6 · ISO K10
ОК6/ БК6 (VK6) is a GOST straight WC-6%Co cemented carbide, the K-group grade equivalent to YG6 and widely traded across Eastern Europe and CIS markets.
Reference datasheet — OK6/BK6 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the VK6 condition
OK6/BK6 tempers and conditions
OK6/BK6 is supplied in 4 conditions, soft to hard. VK6 is the default FabDigit quotes; the values on this page are for it.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
VK6Default ВК6 | Standard medium-grain WC-6Co: best all-round balance of hardness and toughness for cast-iron turning/milling and general wear parts. | — | 1,200 | 0 | 1,580 HV | 80 W/m·K |
ВК6-В | Coarse-grain version for interrupted cuts, rough machining and impact-loaded mining/percussion inserts where toughness matters more than hardness. | — | 1,300 | 0 | 1,400 HV | 85 W/m·K |
ВК6-М | Fine-grain version: higher hardness and edge sharpness for finishing hardened cast iron, non-ferrous alloys, plastics and precision dies; slightly lower toughness. | — | — | — | 1,680 HV | 75 W/m·K |
ВК6-ОМ | Ultrafine (with Cr/Ta grain-growth inhibitors) for micro-drills, PCB tooling and fine finishing of heat-resistant and hardened materials; highest hardness, lowest transverse rupture strength. | — | — | — | 1,780 HV | 70 W/m·K |
What is OK6/BK6?
ОК6/ БК6 (VK6) is a GOST straight WC-6%Co cemented carbide, the K-group grade equivalent to YG6 and widely traded across Eastern Europe and CIS markets. Its low binder content and fine WC grain give high hardness with usable toughness, and it is stocked as rods, strips, inserts, wear buttons and blanks in VK6, VK6-M, VK6-OM and VK6-V variants. Density is 14.8 g/cm³, elastic modulus 630 GPa and thermal conductivity 80 W/m·K, with a maximum service temperature of about 600 °C. Without TiC/TaC it craters quickly when cutting steel, so use a P-group grade such as C7 for steel; move to VK8 for more impact resistance. OK6/BK6 has a density of 14.8 g/cm³ (0.535 lb/in³), heavier than 94% of ceramic grades. It melts at 1,320°C (2,408 °F). OK6/BK6 has a tensile strength of 1,200 MPa (174 ksi), stronger than 94% of ceramic grades. Elongation at break is 0% and the elastic modulus is 630 GPa (91.4 Msi).
What is OK6/BK6 used for?
- cast iron machining
- non-ferrous machining
- general tooling
Advantages
- Stiff — 630 GPa (91.4 Msi), better than 95% of ceramic grades
- Polishes to a fine finish — 92/100, better than 89% of ceramic grades
- Tough — resists crack growth — 9.5 MPa·√m (8.65 ksi·√in), better than 84% of ceramic grades
- Conducts heat well — 80 W/m·K (46.2 BTU/hr·ft·°F), better than 77% of ceramic grades
Limitations
- Heavy — 14.8 g/cm³ (0.535 lb/in³), worse than 94% of ceramic grades
- High embodied carbon — 30 kg CO₂/kg, worse than 91% of ceramic grades
- Needs corrosion protection — 55/100, worse than 77% of ceramic grades
OK6/BK6 properties
Typical room-temperature values for OK6/BK6-VK6; bars are the position among ceramic grades.
Physical3
OK6/BK6 has a density of 14.8 g/cm³ (0.535 lb/in³), heavier than 94% of ceramic grades. It melts at 1,320°C (2,408 °F).
Mechanical13
OK6/BK6 has a tensile strength of 1,200 MPa (174 ksi), stronger than 94% of ceramic grades. Elongation at break is 0% and the elastic modulus is 630 GPa (91.4 Msi).
Thermal5
OK6/BK6 is rated for continuous service to 600°C (1,112 °F). It conducts heat at 80 W/m·K (46.2 BTU/hr·ft·°F), better than 77% of ceramic grades. Thermal expansion is 4.8 µm/m·K (2.67 µin/in·°F).
Electrical2
OK6/BK6 has an electrical resistivity of 2×10⁻⁷ Ω·m.
Chemical & Environmental2
Corrosion resistance is good (55/100), worse than 77% of ceramic grades.
Sustainability4
Producing a kilogram of OK6/BK6 takes about 400 MJ of energy and emits 30 kg of CO₂ — more than 88% of ceramic grades. Typical recycled content is 30%.
Manufacturability3
OK6/BK6's machinability is not recommended (4/100, worse than 85% of ceramic grades).
Common Calculations4
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the ceramic family
Yield strength against density for every ceramic grade FabDigit runs. OK6/BK6 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with OK6/BK6
Is OK6/BK6 easy to machine?
Only diamond grinding, wire/sinker EDM, laser or ultrasonic machining after sintering; green-state pressing/blank machining is the economical route for complex shapes.
Can OK6/BK6 be welded?
Not fusion weldable — join by vacuum/induction brazing with Ag-Cu-Ti or Cu-Mn filler at 700–900 °C, using a ductile Cu interlayer to absorb the CTE mismatch with steel.
Can OK6/BK6 be formed, bent or molded?
Made by wet-milling WC+Co powder, pressing/extrusion or CIP of the green body, then vacuum liquid-phase sintering or sinter-HIP at ~1420 °C with ~18–22% linear shrinkage.
OK6/BK6 chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| Cobinder phase | 5.7 – 6.3 | 6 |
| C (free/total control)carbon balanced to avoid eta phase or free graphite | — | — |
| Cr3C2/TaC (inhibitor, ВК6-М/ОМ only)grain-growth inhibitor in fine/ultrafine variants | 0.2 – 1.5 | 0.6 |
| Fe+Ni+other impurities | ≤ 0.5 | 0.2 |
| WCtungsten carbide hard phase, balance ~94% | balance | — |
What surface finishes work on OK6/BK6?
Diamond lapping/polishing to mirror finish; PVD TiN/TiAlN or CVD coating is common — surface should be micro-blasted and Co-etched before coating; electroplating is rarely used.
Equivalent designations
Standards and trade names that resolve to OK6/BK6 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- ISO
- K10
- GB (China)
- YG6
- GOST
- ОК6/БК6
How much does OK6/BK6 cost?
OK6/BK6 is a high-cost ceramic ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
OK6/BK6 — frequently asked
What is OK6/BK6 used for?
OK6/BK6 is typically used for cast iron machining, non-ferrous machining and general tooling. In short: standard CIS WC-6%Co grade; cast iron and non-ferrous cutting; high modulus, 630 GPa.
What is the tensile strength of OK6/BK6?
OK6/BK6 has a typical tensile strength of 1,200 MPa (174 ksi) — stronger than 94% of ceramic grades. Strength varies by condition: see the 4 listed tempers.
Is OK6/BK6 easy to machine?
Not especially — machinability is rated not recommended (4/100, worse than 85% of ceramic grades). Only diamond grinding, wire/sinker EDM, laser or ultrasonic machining after sintering; green-state pressing/blank machining is the economical route for complex shapes.
Can OK6/BK6 be welded?
Not fusion weldable — join by vacuum/induction brazing with Ag-Cu-Ti or Cu-Mn filler at 700–900 °C, using a ductile Cu interlayer to absorb the CTE mismatch with steel.
What surface finishes work on OK6/BK6?
Diamond lapping/polishing to mirror finish; PVD TiN/TiAlN or CVD coating is common — surface should be micro-blasted and Co-etched before coating; electroplating is rarely used.
Can OK6/BK6 be formed, bent or molded?
Made by wet-milling WC+Co powder, pressing/extrusion or CIP of the green body, then vacuum liquid-phase sintering or sinter-HIP at ~1420 °C with ~18–22% linear shrinkage.
What is the maximum service temperature of OK6/BK6?
OK6/BK6 is rated for continuous use to about 600°C (1,112 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does OK6/BK6 cost?
OK6/BK6 is a high-cost ceramic ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- ГОСТ 3882-74 Сплавы твёрдые спечённые. Марки — Gosstandart / Rosstandart (1974)
- ISO 513 Classification and application of hard cutting materials — ISO (2012)
- ASM Handbook Vol. 2 — Properties of Cemented Carbides — ASM International (1990)
- Cemented carbide grade datasheets (WC-6Co, K10/K20 class) — Zhuzhou Cemented Carbide / Sandvik Hard Materials (2023)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.