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C4 FG

Grade · default condition

GB YG3 · ISO K01

FG = fine grain WC-3Co (1.0–1.5 µm), as-sintered/ground

Standard C4/K01 straight carbide for finishing cast iron and non-ferrous alloys and for general wear parts.

High cost $$$$

Values for the FG condition

Other C4 tempers and conditions

C4 is listed in 2 conditions; see the grade overview at C4.

Compare all 2 conditionsHide
Condition · open for datasheetBest forYield MPaTensile MPaElong. %HardnessConductivity
FGDefaultThis page
Fine grain WC-3Co (1.0–1.5 µm), as-sintered/ground
Standard C4/K01 straight carbide for finishing cast iron and non-ferrous alloys and for general wear parts.—1,20001,850 HV100 W/m·K
Ultrafine/submicron WC-3Co (0.4–0.8 µm), YG3X
Pick when maximum hardness and a keen, chip-free edge are needed — micro-tools, PCB drills, precision dies and slitters.———2,050 HV85 W/m·K

What is C4 FG?

C4 FG is C4 in the FG grade — standard C4/K01 straight carbide for finishing cast iron and non-ferrous alloys and for general wear parts. C4 FG 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 665 GPa (96.5 Msi). C4 FG has a density of 15.2 g/cm³ (0.549 lb/in³), heavier than 100% of ceramic grades. It melts at 1,320°C (2,408 °F).

Advantages

  • Stiff — 665 GPa (96.5 Msi), better than 99% of ceramic grades
  • Polishes to a fine finish — 92/100, better than 89% of ceramic grades
  • Conducts heat well — 100 W/m·K (57.8 BTU/hr·ft·°F), better than 83% of ceramic grades
  • Tough — resists crack growth — 8 MPa·√m (7.28 ksi·√in), better than 77% of ceramic grades

Limitations

  • Heavy — 15.2 g/cm³ (0.549 lb/in³), worse than 100% of ceramic grades
  • High embodied carbon — 30 kg CO₂/kg, worse than 91% of ceramic grades
  • Needs corrosion protection — 45/100, worse than 90% of ceramic grades

C4 FG properties

Typical room-temperature values for C4 FG; 13 are specific to this condition. Other listed values are C4 reference data and may not represent this condition. Bars are the position among ceramic grades.

Physical3

C4 FG has a density of 15.2 g/cm³ (0.549 lb/in³), heavier than 100% of ceramic grades. It melts at 1,320°C (2,408 °F).

Density15.2 g/cm³0.55 lb/in³
Melting Point (Solidus)1,320°C2,408 °F
Porosity0.02%

Mechanical13

C4 FG 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 665 GPa (96.5 Msi).

Elastic (Young's) Modulus665 GPa96.5 Msi
Shear Modulus275 GPa39.9 Msi
Bulk Modulus382 GPa55.4 Msi
Poisson's Ratio0.21
Tensile Strength (Ultimate)1,200 MPa174 ksi
Elongation at Break0%
Compressive Strength6,500 MPa943 ksi
Flexural Strength1,600 MPa232 ksi
Shear Strength1,200 MPa174 ksi
Fracture Toughness (K_IC)8 MPa·√m7.3 ksi·√in
Hardness, Vickers1,850 HV
Hardness, Knoop1,800 HK
Hardness, Mohs9

Thermal5

C4 FG is rated for continuous service to 600°C (1,112 °F). It conducts heat at 100 W/m·K (57.8 BTU/hr·ft·°F), better than 83% of ceramic grades. Thermal expansion is 4.5 µm/m·K (2.5 µin/in·°F).

Thermal Conductivity100 W/m·K57.8 BTU/hr·ft·°F
Specific Heat Capacity210 J/kg·K0.05 BTU/lb·°F
Thermal Expansion (CTE, 20–100 °C)4.5 µm/m·K2.5 µin/in·°F
Max Service Temperature (continuous)600°C1,112 °F
Min Service Temperature-196°C-321 °F

Electrical2

C4 FG has an electrical resistivity of 1.9×10⁻⁷ Ω·m.

Electrical Resistivity1.9×10⁻⁷ Ω·m7.48 µΩ·in
Volume Resistivity1.9×10⁻⁵ Ω·cm

Chemical & Environmental2

Corrosion resistance is fair (45/100), worse than 90% of ceramic grades.

Corrosion ResistanceFair45/100
Chemical Resistance SummaryWC skeleton is chemically very stable; the cobalt binder is leached by mineral acids (HCl, H2SO4, HNO3), by strong alkalis at temperature and by acidic coolants, causing surface embrittlement. Good against neutral coolants, oils, solvents and molten non-ferrous metals; oxidises rapidly in air above ~600 °C.

Sustainability4

Producing a kilogram of C4 FG takes about 400 MJ of energy and emits 30 kg of CO₂ — more than 88% of ceramic grades. Typical recycled content is 30%.

Embodied Energy (primary production)400 MJ/kg171,969 BTU/lb
Embodied Carbon (primary production)30 kg CO₂/kg
Embodied Water300 L/kg35.9 gal/lb
Typical Recycled Content30%

Manufacturability3

C4 FG's machinability is not recommended (3/100, worse than 95% of ceramic grades).

MachinabilityNot recommended3/100
PolishabilityExcellent92/100
Sintering / Firing Temperature1,420°C2,588 °F

Common Calculations4

Specific Strength (UTS / density)calculated79 kN·m/kg
Specific Stiffness (E / density)calculated43.8 MN·m/kg
Thermal Diffusivitycalculated31.3 mm²/s
Thermal Shock Resistance Indexcalculated40

Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.

Working with C4 FG

Is C4 easy to machine?

Only diamond grinding, wire/sinker EDM, laser or ultrasonic machining — never conventional cutting; grind wet with generous coolant to avoid thermal cracks.

Can C4 be welded?

Not fusion weldable; join by vacuum or induction brazing with Ag-Cu-(Ti/Ni) filler below ~900 °C, using a shim to absorb CTE mismatch with steel.

Can C4 be formed, bent or molded?

Net-shape by pressing or extruding WC-Co powder with binder then vacuum/sinter-HIP at ~1420 °C with ~18–22 % linear shrinkage; no plastic forming after sintering.

What surface finishes work on C4?

Diamond lapping/polishing to mirror finish; PVD TiN/TiAlN or CVD coatings and micro-blast edge honing are standard for cutting tools.

C4 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.

ElementSpec limit (wt %)Nominal
Cobinder phase; defines toughness/hardness balance2.5 – 43
TiC+TaC+NbCstraight grade — cubic carbides only as trace grain-growth inhibitor level0 – 0.50
Cr3C2/VCgrain-growth inhibitor, mainly in the ultrafine variant0 – 0.80.4
WCbalance, ~96 wt %; total C ≈ 5.9 %balance—

C4 FG — frequently asked

What is C4 FG used for?

C4 FG is typically used for precision finishing, wire drawing dies and fine boring. In short: hardest US straight carbide; stiffest grade, 665 GPa; light-cut finishing only.

What is the tensile strength of C4 FG?

C4 FG has a typical tensile strength of 1,200 MPa (174 ksi) — stronger than 94% of ceramic grades. Strength varies by condition: see the 2 listed tempers.

Is C4 FG easy to machine?

Not especially — machinability is rated not recommended (3/100, worse than 95% of ceramic grades). Only diamond grinding, wire/sinker EDM, laser or ultrasonic machining — never conventional cutting; grind wet with generous coolant to avoid thermal cracks.

Can C4 FG be welded?

Not fusion weldable; join by vacuum or induction brazing with Ag-Cu-(Ti/Ni) filler below ~900 °C, using a shim to absorb CTE mismatch with steel.

What surface finishes work on C4 FG?

Diamond lapping/polishing to mirror finish; PVD TiN/TiAlN or CVD coatings and micro-blast edge honing are standard for cutting tools.

Can C4 FG be formed, bent or molded?

Net-shape by pressing or extruding WC-Co powder with binder then vacuum/sinter-HIP at ~1420 °C with ~18–22 % linear shrinkage; no plastic forming after sintering.

What is the maximum service temperature of C4 FG?

C4 FG 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.

Sources

  1. ISO 513 — Classification of hard cutting materials (K01 application group) — ISO (2012)
  2. ASTM B276 / B406 — Apparent porosity and transverse rupture strength of cemented carbides — ASTM (2020)
  3. ASM Handbook Vol. 2 — Properties of Cemented Carbides — ASM International (1990)
  4. Straight-grade WC-Co hardmetal property tables — Kennametal / Sandvik Hard Materials / Zhuzhou Cemented Carbide (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.