Graphite
Graphite is a polycrystalline synthetic carbon covered by ASTM C709 and supplied as isostatic (ISO), ultra-fine isostatic (ISO-UF), extruded (EXT), moulded (MLD), resin-impregnated (RI) and pyrolytic (PYRO) grades.
Reference datasheet — 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.
Graphite tempers and conditions
Graphite is supplied in 2 conditions, soft to hard.
Compare all 2 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Die/vibration-moulded medium-grain graphite | Cost-effective medium-grain grade for large moulds, casting dies, sintering trays and roughing EDM electrodes. | 20 | 120 W/m·K | |||
Pyrolytic graphite | Use for thermal-spreader, crucible-liner and thermal-barrier duty where extreme in-plane conductivity plus through-plane insulation and zero permeability are needed. | 90 | 400 W/m·K |
Supply forms, finishes and certifications
Ways Graphite is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
EXT | Extruded coarse-grain graphite | Supply form |
RI | Resin-impregnated impervious graphite | Surface finish |
ISODefault | Isostatically pressed fine-grain graphite | Certification |
ISO-UF | Ultrafine-grain high-purity isostatic graphite | Certification |
What is Graphite?
Graphite is a polycrystalline synthetic carbon covered by ASTM C709 and supplied as isostatic (ISO), ultra-fine isostatic (ISO-UF), extruded (EXT), moulded (MLD), resin-impregnated (RI) and pyrolytic (PYRO) grades. At 1.78 g/cm³ with 110 W/m·K thermal conductivity, self-lubrication, good thermal-shock resistance and a machinability score of 92, it is used for fast-cut EDM electrodes and high-temperature tooling, supplied as blocks, rods and tubes. Strength is low (30 MPa tensile, 11 GPa modulus) and oxidation in air limits service to about 450 °C, so higher temperatures require inert or vacuum atmospheres or a SiC coating; copper is the alternative electrode material for fine detail. Graphite has a density of 1.78 g/cm³ (0.0643 lb/in³), lighter than 90% of ceramic grades. It melts at 3,650°C (6,602 °F). Graphite has a tensile strength of 30 MPa (4.35 ksi), weaker than 77% of ceramic grades. The elastic modulus is 11 GPa (1.6 Msi).
What is Graphite used for?
- EDM electrodes
- continuous casting molds
- crucibles
- semiconductor furnace parts
- electrodes
Advantages
- Easy to machine — 92/100, better than 97% of ceramic grades
- Lightweight — 1.78 g/cm³ (0.0643 lb/in³), better than 90% of ceramic grades
- Conducts heat well — 110 W/m·K (63.6 BTU/hr·ft·°F), better than 86% of ceramic grades
Limitations
- Hard to polish — 35/100, worse than 93% of ceramic grades
- Low stiffness — 11 GPa (1.6 Msi), worse than 91% 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
Graphite properties
Typical room-temperature values; bars are the position among ceramic grades.
Physical3
Graphite has a density of 1.78 g/cm³ (0.0643 lb/in³), lighter than 90% of ceramic grades. It melts at 3,650°C (6,602 °F).
Mechanical10
Graphite has a tensile strength of 30 MPa (4.35 ksi), weaker than 77% of ceramic grades. The elastic modulus is 11 GPa (1.6 Msi).
Thermal5
Graphite is rated for continuous service to 450°C (842 °F). It conducts heat at 110 W/m·K (63.6 BTU/hr·ft·°F), better than 86% of ceramic grades. Thermal expansion is 4.5 µm/m·K (2.5 µin/in·°F).
Electrical2
Graphite has an electrical resistivity of 1.1×10⁻⁵ Ω·m.
Chemical & Environmental2
Corrosion resistance is very good (80/100), better than 56% of ceramic grades.
Sustainability4
Producing a kilogram of Graphite takes about 120 MJ of energy and emits 9 kg of CO₂ — more than 51% of ceramic grades. Typical recycled content is 10%.
Manufacturability3
Graphite's machinability is excellent (92/100, better than 97% 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. Graphite is highlighted; hover a dot for its name, or open the interactive family chart.
Working with Graphite
Is Graphite easy to machine?
Machines dry and fast with carbide or PCD tooling (no coolant); requires vacuum dust extraction and sharp tools since the dust is abrasive and electrically conductive.
Can Graphite be welded?
Not weldable — parts are joined mechanically (graphite bolts/threads) or with carbon/graphite cement cured and re-baked.
Can Graphite be formed, bent or molded?
Net shape comes from cold isostatic pressing, extrusion or vibration moulding of coke/pitch mix, then baking ~1000 °C, optional pitch re-impregnation and graphitization at 2600–3000 °C; final geometry is achieved by machining, not forming.
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 |
|---|---|---|
| ashresidual Si, Al, Fe, Ca, V oxides; halogen-purified grades <20 ppm | 0 – 0.3 | 0.05 |
| Sfrom petroleum/needle coke feedstock | ≤ 0.05 | 0.02 |
| phenolic resin impregnantonly in impervious (RI) variant | 0 – 15 | 0 |
| Cfixed carbon after graphitization; purified grades reach ≥99.99 % | ≥ 99 (balance) |
What surface finishes work on Graphite?
Common finishes are resin/metal impregnation for imperviousness, halogen purification to <20 ppm ash, and CVD SiC or pyrolytic-carbon coating for oxidation and particle-shedding control; no plating or painting.
Equivalent designations
Standards and trade names that resolve to Graphite in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Similar grades
- C709
How much does Graphite cost?
Graphite is a high-cost ceramic ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Graphite — frequently asked
What is Graphite used for?
Graphite is typically used for EDM electrodes, continuous casting molds, crucibles, semiconductor furnace parts and electrodes. In short: fastest-machining ceramic material; self-lubricating high-temperature carbon; standard EDM electrode material.
What is the tensile strength of Graphite?
Graphite has a typical tensile strength of 30 MPa (4.35 ksi) — weaker than 77% of ceramic grades. Strength varies by condition: see the 2 listed tempers.
Is Graphite easy to machine?
Yes — machinability is rated excellent (92/100, better than 97% of ceramic grades). Machines dry and fast with carbide or PCD tooling (no coolant); requires vacuum dust extraction and sharp tools since the dust is abrasive and electrically conductive.
Can Graphite be welded?
Not weldable — parts are joined mechanically (graphite bolts/threads) or with carbon/graphite cement cured and re-baked.
What surface finishes work on Graphite?
Common finishes are resin/metal impregnation for imperviousness, halogen purification to <20 ppm ash, and CVD SiC or pyrolytic-carbon coating for oxidation and particle-shedding control; no plating or painting.
Can Graphite be formed, bent or molded?
Net shape comes from cold isostatic pressing, extrusion or vibration moulding of coke/pitch mix, then baking ~1000 °C, optional pitch re-impregnation and graphitization at 2600–3000 °C; final geometry is achieved by machining, not forming.
What is the maximum service temperature of Graphite?
Graphite is rated for continuous use to about 450°C (842 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does Graphite cost?
Graphite is a high-cost ceramic ($$$$), 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 International (2021)
- ASTM C651 / C695 / C749 / C611 — flexural, compressive, tensile and resistivity test methods for graphite — ASTM International (2020)
- IG-11 / ISO-88 isotropic graphite property sheets — Toyo Tanso (2022)
- EDM-3 / AXF-5Q ultrafine graphite properties — Entegris (POCO Graphite) (2021)
- Specialty graphite grades R6650, R6300, extruded grades — SGL Carbon (2022)
- Impervious graphite (Graphilor) and isostatic grade data — Mersen (2021)
- Engineered Materials Handbook Vol. 4 — Ceramics and Glasses / carbon-graphite properties — 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.