CBN PCBN-L
Grade
also Borazon
PCBN-L = low-CBN-content sintered blank
Choose for continuous finish hard turning of 55–65 HRC bearing/gear steels where wear resistance and edge integrity beat impact toughness.
Values for the PCBN-L condition
Other CBN tempers and conditions
CBN is listed in 3 conditions; see the grade overview at CBN.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Microcrystalline / polycrystalline CBN micron powder | Choose for fine lapping/polishing slurries and high-toughness resin-bond superfinishing where self-sharpening blocky micro-grain is wanted. | — | 350 | 0 | 4,000 HV | 300 W/m·K |
PCBN-LThis page Low-CBN-content sintered blank | Choose for continuous finish hard turning of 55–65 HRC bearing/gear steels where wear resistance and edge integrity beat impact toughness. | — | — | — | 2,800 HV | 44 W/m·K |
High-CBN-content sintered blank | Choose for interrupted/heavy hard turning, milling of grey and chilled cast iron, hardfacing and sintered iron where impact toughness and heat conduction dominate. | — | — | — | 3,200 HV | 120 W/m·K |
What is CBN PCBN-L?
CBN PCBN-L is CBN in the PCBN-L grade — choose for continuous finish hard turning of 55–65 HRC bearing/gear steels where wear resistance and edge integrity beat impact toughness. The elastic modulus is 580 GPa (84.1 Msi). CBN PCBN-L has a density of 4.3 g/cm³ (0.155 lb/in³), lighter than 56% of ceramic grades. It melts at 2,973°C (5,383 °F).
Advantages
- Good corrosion resistance — 93/100, better than 94% of ceramic grades
- Stiff — 580 GPa (84.1 Msi), better than 89% of ceramic grades
- Polishes to a fine finish — 90/100, better than 78% of ceramic grades
Limitations
- High embodied carbon — 55 kg CO₂/kg, worse than 97% of ceramic grades
CBN PCBN-L properties
Typical room-temperature values for CBN PCBN-L; 13 are specific to this condition. Other listed values are CBN reference data and may not represent this condition. Bars are the position among ceramic grades.
Physical4
CBN PCBN-L has a density of 4.3 g/cm³ (0.155 lb/in³), lighter than 56% of ceramic grades. It melts at 2,973°C (5,383 °F).
Mechanical8
The elastic modulus is 580 GPa (84.1 Msi).
Thermal5
CBN PCBN-L is rated for continuous service to 1,100°C (2,012 °F). It conducts heat at 44 W/m·K (25.4 BTU/hr·ft·°F), better than 68% of ceramic grades. Thermal expansion is 5.5 µm/m·K (3.06 µin/in·°F).
Electrical3
CBN PCBN-L has an electrical resistivity of 1×10⁻⁴ Ω·m.
Chemical & Environmental2
Corrosion resistance is excellent (93/100), better than 94% of ceramic grades.
Sustainability3
Producing a kilogram of CBN PCBN-L takes about 900 MJ of energy and emits 55 kg of CO₂ — more than 96% of ceramic grades. Typical recycled content is 5%.
Manufacturability3
CBN PCBN-L's machinability is not recommended (3/100, worse than 95% of ceramic grades).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with CBN PCBN-L
Is CBN easy to machine?
Not machinable by conventional means — shaped by diamond grinding/lapping, laser or wire-EDM (only conductive TiC/TiN- or metal-bonded PCBN is EDM-capable).
Can CBN be welded?
Not weldable; PCBN wafers are vacuum-brazed to WC-Co carbide substrates with Ag-Cu-Ti active filler below ~900 °C to avoid back-conversion to hBN.
Can CBN be formed, bent or molded?
Formed only by HPHT synthesis/sintering at 5–8 GPa and 1350–1800 °C; grit is then shape-graded, coated (Ni/Ti) and bonded into resin, vitrified or electroplated wheels.
What surface finishes work on CBN?
Cutting edges are diamond-lapped or honed to a T-land/chamfer; abrasive grit is nickel- or titanium-clad to improve bond retention and heat transfer.
CBN 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 |
|---|---|---|
| Bstoichiometric BN, zincblende structure | 43 – 44 | 43.6 |
| Li/Mg/Ca (catalyst residue)nitride catalyst residues in HPHT grit; imparts amber/black colour | 0 – 1 | 0.3 |
| AlN/AlB2 binder (PCBN-H only)sintering aid in high-content polycrystalline blanks | 5 – 15 | 10 |
| TiC/TiN binder (PCBN-L only)ceramic binder phase in low-content polycrystalline blanks | 35 – 55 | 45 |
| N | ≥ 56 (balance) | — |
CBN PCBN-L — frequently asked
What is CBN PCBN-L used for?
CBN PCBN-L is typically used for cutting tool inserts (PCBN), grinding wheel abrasive, honing hardened steel and high-speed machining of superalloys. In short: second-hardest known material; ferrous-safe superabrasive; hard-turning tool phase.
Is CBN PCBN-L easy to machine?
Not especially — machinability is rated not recommended (3/100, worse than 95% of ceramic grades). Not machinable by conventional means — shaped by diamond grinding/lapping, laser or wire-EDM (only conductive TiC/TiN- or metal-bonded PCBN is EDM-capable).
Can CBN PCBN-L be welded?
Not weldable; PCBN wafers are vacuum-brazed to WC-Co carbide substrates with Ag-Cu-Ti active filler below ~900 °C to avoid back-conversion to hBN.
What surface finishes work on CBN PCBN-L?
Cutting edges are diamond-lapped or honed to a T-land/chamfer; abrasive grit is nickel- or titanium-clad to improve bond retention and heat transfer.
Can CBN PCBN-L be formed, bent or molded?
Formed only by HPHT synthesis/sintering at 5–8 GPa and 1350–1800 °C; grit is then shape-graded, coated (Ni/Ti) and bonded into resin, vitrified or electroplated wheels.
What is the maximum service temperature of CBN PCBN-L?
CBN PCBN-L is rated for continuous use to about 1,100°C (2,012 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- Engineered Materials Handbook, Vol. 4: Ceramics and Glasses — ASM International (1991)
- ASM Handbook Vol. 16: Machining — Superabrasives and PCBN tooling — ASM International (1989)
- PCBN grade and CBN abrasive technical data — Element Six (2023)
- CBN turning grade selection data (CB7015/CB7025 class) — Sandvik Coromant (2023)
- GB/T 23536 (Cubic boron nitride) — SAC/ (2009)
- Semiconductor and elastic properties of cubic boron nitride — Landolt-Börnstein / Ioffe compilations (2001)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.