Isostatic Graphite
Isostatic Graphite is a fine-grain, isotropic carbon produced by cold isostatic pressing, baking and graphitisation, supplied in grain grades FG-10, UFG-5 and SFG-2 plus the 5N-purity HP-5N.
Reference datasheet — Isostatic Graphite 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 FG-10 condition
Isostatic Graphite tempers and conditions
Isostatic Graphite is supplied in 4 conditions, soft to hard. FG-10 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 |
|---|---|---|---|---|---|---|
FG-10Default Fine grain (~10–20 µm), general-purpose isostatic graphite | Use the fine-grain (~10–20 µm) general-purpose grade as the cost-effective choice for roughing EDM electrodes, continuous-casting moulds, heating elements and general hot-zone parts. | 27 | 105 W/m·K | |||
Halogen-purified high-purity grade | Use the halogen-purified grade (ash < 5 ppm) for monocrystalline silicon and sapphire hot zones, crucibles, epitaxy and semiconductor fixtures where metal contamination is prohibited. | 27 | 120 W/m·K | |||
Ultra-fine grain (~5 µm) EDM electrode grade | Pick the ultra-fine-grain (~5 µm) grade as the mainstream EDM electrode material for stable discharge, low electrode wear and moderately fine rib detail. | 35 | 90 W/m·K | |||
Superfine grain (≤2 µm), high-density precision grade | Choose the superfine-grain (≤2 µm) high-density grade for mirror-finish and micro EDM electrodes, optical moulds and fine structures needing 55 MPa tensile strength and the finest discharge texture. | 55 | 70 W/m·K |
What is Isostatic Graphite?
Isostatic Graphite is a fine-grain, isotropic carbon produced by cold isostatic pressing, baking and graphitisation, supplied in grain grades FG-10, UFG-5 and SFG-2 plus the 5N-purity HP-5N. Engineers use it where uniform properties in all directions and fine detail matter — EDM electrodes, hot-press moulds and semiconductor fixtures machined from solid block. It offers 27 MPa tensile strength, 1.77 g/cm3 density, 11 GPa modulus, 105 W/m·K and a corrosion-resistance score of 75, but oxidises in air above about 450 °C, is brittle, and costs more than extruded graphite, which is the alternative when tolerance and grain size are less critical. Isostatic Graphite has a density of 1.77 g/cm³ (0.0639 lb/in³), lighter than 91% of ceramic grades. It melts at 3,650°C (6,602 °F). Isostatic Graphite has a tensile strength of 27 MPa (3.92 ksi), weaker than 82% of ceramic grades. The elastic modulus is 11 GPa (1.6 Msi).
What is Isostatic Graphite used for?
- EDM electrodes
- hot-press molds
- semiconductor fixtures
- continuous casting dies
Advantages
- Easy to machine — 90/100, better than 94% of ceramic grades
- Lightweight — 1.77 g/cm³ (0.0639 lb/in³), better than 91% of ceramic grades
- Conducts heat well — 105 W/m·K (60.7 BTU/hr·ft·°F), better than 85% of ceramic grades
Limitations
- Low stiffness — 11 GPa (1.6 Msi), worse than 91% of ceramic grades
- Hard to polish — 45/100, worse than 88% of ceramic grades
- Low fracture toughness — 1 MPa·√m (0.91 ksi·√in), worse than 84% of ceramic grades
- Limited service temperature — 450°C (842 °F), worse than 77% of ceramic grades
Isostatic Graphite properties
Typical room-temperature values for Isostatic Graphite-FG-10; bars are the position among ceramic grades.
Physical3
Isostatic Graphite has a density of 1.77 g/cm³ (0.0639 lb/in³), lighter than 91% of ceramic grades. It melts at 3,650°C (6,602 °F).
Mechanical10
Isostatic Graphite has a tensile strength of 27 MPa (3.92 ksi), weaker than 82% of ceramic grades. The elastic modulus is 11 GPa (1.6 Msi).
Thermal5
Isostatic Graphite is rated for continuous service to 450°C (842 °F). It conducts heat at 105 W/m·K (60.7 BTU/hr·ft·°F), better than 85% of ceramic grades. Thermal expansion is 4.5 µm/m·K (2.5 µin/in·°F).
Electrical2
Isostatic Graphite has an electrical resistivity of 1.1×10⁻⁵ Ω·m.
Chemical & Environmental2
Corrosion resistance is very good (75/100), better than 50% of ceramic grades.
Sustainability4
Producing a kilogram of Isostatic Graphite takes about 190 MJ of energy and emits 16 kg of CO₂ — more than 62% of ceramic grades. Typical recycled content is 5%.
Manufacturability3
Isostatic Graphite's machinability is excellent (90/100, better than 94% 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. Isostatic Graphite is highlighted; hover a dot for its name, or open the interactive family chart.
Working with Isostatic Graphite
Is Isostatic Graphite easy to machine?
Cut dry with no coolant, using carbide or PCD tooling at high spindle speed and light feed. Explosion-rated vacuum dust extraction is required, and exit edges should be chamfered to prevent break-out.
Can Isostatic Graphite be welded?
Not weldable; assemblies are made with graphite threaded joints, graphite tenon joints, or carbon cement with a carbonising binder.
Can Isostatic Graphite be formed, bent or molded?
Shaped only by machining or wire EDM from pressed and graphitised blanks; no plastic forming is possible. Large parts must be nested to the available blank sizes.
Isostatic Graphite 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 |
|---|---|---|
| ashstandard grade ash ≤500–1000 ppm; halogen-purified <5 ppm (HP-5N) | 5×10⁻⁴ – 0.1 | 0.03 |
| Sresidual sulfur, very low after graphitization | ≤ 0.03 | 0.01 |
| Femain metallic ash impurity; <1 ppm in purified grades | ≤ 0.01 | 0 |
| Cfixed carbon; needle/pitch coke + pitch binder, 2800–3000 °C | ≥ 99.9 (balance) |
What surface finishes work on Isostatic Graphite?
Grind to final size and ultrasonically clean to remove residual dust. For oxidation resistance apply SiC, pyrolytic-carbon or CVD coatings, or phosphate impregnation; high-purity applications require halogen-atmosphere purification.
How much does Isostatic Graphite cost?
Isostatic Graphite 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.
Isostatic Graphite — frequently asked
What is Isostatic Graphite used for?
Isostatic Graphite is typically used for EDM electrodes, hot-press molds, semiconductor fixtures and continuous casting dies. In short: finest-grain isotropic graphite; strongest common graphite grade; 5N purity available.
What is the tensile strength of Isostatic Graphite?
Isostatic Graphite has a typical tensile strength of 27 MPa (3.92 ksi) — weaker than 82% of ceramic grades. Strength varies by condition: see the 4 listed tempers.
Is Isostatic Graphite easy to machine?
Yes — machinability is rated excellent (90/100, better than 94% of ceramic grades). Cut dry with no coolant, using carbide or PCD tooling at high spindle speed and light feed. Explosion-rated vacuum dust extraction is required, and exit edges should be chamfered to prevent break-out.
Can Isostatic Graphite be welded?
Not weldable; assemblies are made with graphite threaded joints, graphite tenon joints, or carbon cement with a carbonising binder.
What surface finishes work on Isostatic Graphite?
Grind to final size and ultrasonically clean to remove residual dust. For oxidation resistance apply SiC, pyrolytic-carbon or CVD coatings, or phosphate impregnation; high-purity applications require halogen-atmosphere purification.
Can Isostatic Graphite be formed, bent or molded?
Shaped only by machining or wire EDM from pressed and graphitised blanks; no plastic forming is possible. Large parts must be nested to the available blank sizes.
What is the maximum service temperature of Isostatic Graphite?
Isostatic Graphite is rated for continuous use to about 450°C (842 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does Isostatic Graphite cost?
Isostatic Graphite 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
- ASTM C709 — Standard Terminology Relating to Manufactured Carbon and Graphite — ASTM (2021)
- ASTM C651 / C695 / C749 — Flexural, Compressive and Tensile Testing of Graphite — ASTM (2020)
- IG-11 / IG-43 / IG-56 Isotropic Graphite Property Sheets — Toyo Tanso (2022)
- SIGRAFINE isostatic graphite grades (R6650, R6710) — SGL Carbon (2022)
- Properties and Characteristics of Graphite (EDM-3, EDM-AF5) — POCO Graphite / Entegris (2015)
- ASM Engineered Materials Handbook Vol. 4 — Ceramics and Glasses (carbon & graphite) — ASM International (1991)
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.