C8 UC (Uncoated C8)
Grade · default condition
GB YT30 · ISO P10
Use the general-purpose uncoated C8/P10 finishing substrate for high-speed finish turning, fine boring and form tools on steel.
Values for the UC condition
Other C8 tempers and conditions
C8 is listed in 2 conditions; see the grade overview at C8.
- UC
- YT30
Compare all 2 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
UCDefaultThis page Uncoated C8 | Use the general-purpose uncoated C8/P10 finishing substrate for high-speed finish turning, fine boring and form tools on steel. | — | — | — | 1,650 HV | 30 W/m·K |
GB grade WC–30TiC–4Co, highest hardness / lowest toughness | Pick the WC–30TiC–4Co composition for the hardest, highest-speed finish turning and boring of steel, but restrict it to light continuous cuts and never interrupted cutting. | — | — | — | 1,780 HV | 21 W/m·K |
What is C8 UC?
C8 UC is C8 in the UC grade — use the general-purpose uncoated C8/P10 finishing substrate for high-speed finish turning, fine boring and form tools on steel. C8 UC has a tensile strength of 900 MPa (131 ksi), stronger than 83% of ceramic grades. Elongation at break is 0% and the elastic modulus is 520 GPa (75.4 Msi). C8 UC has a density of 10.4 g/cm³ (0.376 lb/in³), heavier than 78% of ceramic grades. It melts at 1,320°C (2,408 °F).
Advantages
- Polishes to a fine finish — 92/100, better than 89% of ceramic grades
- Stiff — 520 GPa (75.4 Msi), better than 81% of ceramic grades
Limitations
- Heavy — 10.4 g/cm³ (0.376 lb/in³), worse than 78% of ceramic grades
- Needs corrosion protection — 55/100, worse than 77% of ceramic grades
C8 UC properties
Typical room-temperature values for C8 UC; 10 are specific to this condition. Other listed values are C8 reference data and may not represent this condition. Bars are the position among ceramic grades.
Physical3
C8 UC has a density of 10.4 g/cm³ (0.376 lb/in³), heavier than 78% of ceramic grades. It melts at 1,320°C (2,408 °F).
Mechanical13
C8 UC has a tensile strength of 900 MPa (131 ksi), stronger than 83% of ceramic grades. Elongation at break is 0% and the elastic modulus is 520 GPa (75.4 Msi).
Thermal5
C8 UC is rated for continuous service to 900°C (1,652 °F). It conducts heat at 30 W/m·K (17.3 BTU/hr·ft·°F), better than 60% of ceramic grades. Thermal expansion is 6.5 µm/m·K (3.61 µin/in·°F).
Electrical2
C8 UC has an electrical resistivity of 5×10⁻⁷ Ω·m.
Chemical & Environmental2
Corrosion resistance is good (55/100), worse than 77% of ceramic grades.
Sustainability4
Producing a kilogram of C8 UC takes about 90 MJ of energy and emits 6.5 kg of CO₂ — less than 62% of ceramic grades. Typical recycled content is 30%.
Manufacturability3
C8 UC's machinability is not recommended (5/100, worse than 59% of ceramic grades).
Common Calculations4
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C8 UC
Is C8 easy to machine?
Shape only by diamond wheel grinding, wire EDM or laser; conventional cutting tools cannot be used, and grinding must be flooded with coolant to prevent thermal cracking.
Can C8 be welded?
Not fusion weldable; braze to steel bodies with silver fillers (BAg-1/BAg-3) in vacuum or by induction, using preheat and slow cooling to manage the CTE mismatch.
Can C8 be formed, bent or molded?
Near-net-shape powder metallurgy: die pressing, extrusion or powder injection moulding followed by liquid-phase sintering or sinter-HIP at 1400–1500 °C; allow for about 18–20 % sintering shrinkage in the tooling.
What surface finishes work on C8?
Diamond lapping and polishing produce a mirror cutting edge; CVD (TiCN-Al₂O₃-TiN) or PVD (TiAlN) coatings are common, with edge honing carried out before coating.
C8 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; C8 uses lower limit for higher hardness | 4 – 7 | 5.5 |
| TiCresists crater wear; YT30 contains 30 % | 8 – 30 | 14 |
| TaC+NbCrefines grain, improves hot strength | 0 – 8 | 4 |
| WCmain hard phase | balance | — |
C8 UC — frequently asked
What is C8 UC used for?
C8 UC is typically used for precision steel finishing, fine boring of steel and high-speed light turning. In short: hardest P-group carbide; precision finishing only; low cobalt, low toughness.
What is the tensile strength of C8 UC?
C8 UC has a typical tensile strength of 900 MPa (131 ksi) — stronger than 83% of ceramic grades. Strength varies by condition: see the 2 listed tempers.
Is C8 UC easy to machine?
Not especially — machinability is rated not recommended (5/100, worse than 59% of ceramic grades). Shape only by diamond wheel grinding, wire EDM or laser; conventional cutting tools cannot be used, and grinding must be flooded with coolant to prevent thermal cracking.
Can C8 UC be welded?
Not fusion weldable; braze to steel bodies with silver fillers (BAg-1/BAg-3) in vacuum or by induction, using preheat and slow cooling to manage the CTE mismatch.
What surface finishes work on C8 UC?
Diamond lapping and polishing produce a mirror cutting edge; CVD (TiCN-Al₂O₃-TiN) or PVD (TiAlN) coatings are common, with edge honing carried out before coating.
Can C8 UC be formed, bent or molded?
Near-net-shape powder metallurgy: die pressing, extrusion or powder injection moulding followed by liquid-phase sintering or sinter-HIP at 1400–1500 °C; allow for about 18–20 % sintering shrinkage in the tooling.
What is the maximum service temperature of C8 UC?
C8 UC is rated for continuous use to about 900°C (1,652 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- ASTM B777 / C-grade classification for cemented carbides — ASTM (2015)
- ISO 513 Classification and application of hard cutting materials — ISO (2012)
- ASM Handbook Vol.16 Machining — Cemented Carbides — ASM International (1989)
- ASM Handbook Vol.7 Powder Metallurgy — Cemented Carbide Processing — ASM International (2015)
- ( / Kennametal / Sandvik Coromant) (2023)
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.