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Pyrolytic Graphite vs RP Graphite Electrode

Ceramic · grade comparison

Pyrolytic Graphite and RP Graphite Electrode are both ceramic grades. Pyrolytic Graphite is the stronger of the two: tensile strength 100 MPa (14.5 ksi) against 7 MPa (1.02 ksi) for RP Graphite Electrode, about 14 times as much. Pyrolytic Graphite is the more ductile: elongation 0.3% versus 0.25% for RP Graphite Electrode. RP Graphite Electrode is lighter (1.56 g/cm³ vs 2.2 g/cm³ for Pyrolytic Graphite) and Pyrolytic Graphite is stiffer (30 GPa vs 9 GPa). On the shop floor, RP Graphite Electrode machines more easily (excellent vs good) and RP Graphite Electrode sits in a lower cost tier (standard, $$) than Pyrolytic Graphite (high, $$$$).

Pyrolytic GraphiteChoose it when strength drives the design, or when the part is bent, formed or impact-loaded.

RP Graphite ElectrodeChoose it when weight is the constraint, or when the part is machined in volume.

Pyrolytic Graphite vs RP Graphite Electrode: properties

Pyrolytic GraphiteRP Graphite Electrode

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

30 GPa4.4 Msi
9 GPa1.3 Msi

Shear Modulus

4.5 GPa0.65 Msi
3.8 GPa0.55 Msi

Bulk Modulus

34 GPa4.9 Msi
—

Poisson's Ratio

0.17
0.15

Tensile Strength (Ultimate)

100 MPa14.5 ksi
7 MPa1 ksi

Elongation at Break

0.3%
0.25%

Compressive Strength

150 MPa21.8 ksi
22 MPa3.2 ksi

Flexural Strength

90 MPa13.1 ksi
11 MPa1.5 ksi

Shear Strength

5 MPa0.73 ksi
6 MPa0.87 ksi

Hardness, Mohs

1
1.5

Hardness, Vickers

—
32 HV

Same in both: Fracture Toughness (K_IC) 1 MPa·√m0.91 ksi·√in

Physical

Density and transition temperatures.

Density

2.2 g/cm³0.08 lb/in³
1.56 g/cm³0.06 lb/in³

Porosity

0.5%
25%

Same in both: Melting Point (Solidus) 3,650°C6,602 °F

Thermal

How each material carries heat and how hot it can run.

Thermal Conductivity

300 W/m·K173 BTU/hr·ft·°F
140 W/m·K80.9 BTU/hr·ft·°F

Thermal Expansion (CTE, 20–100 °C)

1 µm/m·K0.56 µin/in·°F
2.2 µm/m·K1.2 µin/in·°F

Min Service Temperature

-269°C-452 °F
-200°C-328 °F

Same in both: Specific Heat Capacity 710 J/kg·K0.17 BTU/lb·°F · Max Service Temperature (continuous) 450°C842 °F

Electrical

Conductivity and insulation.

Electrical Resistivity

5×10⁻⁶ Ω·m197 µΩ·in
8×10⁻⁶ Ω·m315 µΩ·in

Volume Resistivity

5×10⁻⁴ Ω·cm
8×10⁻⁴ Ω·cm

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

85 / 100
65 / 100

Manufacturability

FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.

Machinability

55 / 100
90 / 100

Polishability

70 / 100
25 / 100

Sintering / Firing Temperature

2,100°C3,812 °F
2,900°C5,252 °F

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

350 MJ/kg150,473 BTU/lb
65 MJ/kg27,945 BTU/lb

Embodied Carbon (primary production)

25 kg CO₂/kg
6 kg CO₂/kg

Typical Recycled Content

0%
5%

Embodied Water

—
25 L/kg3 gal/lb

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

45 kN·m/kg
4 kN·m/kg

Specific Stiffness (E / density)

13.6 MN·m/kg
5.8 MN·m/kg

Thermal Diffusivity

192.1 mm²/s
126.4 mm²/s

Thermal Shock Resistance Index

1,000
49

Strength versus weight

Yield strength against density for every ceramic grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.

501002005001,000234567Density (g/cm³)Yield strength (MPa) — log scale

Manufacturing and finishing

CapabilityPyrolytic GraphiteRP Graphite Electrode
Default condition——
Relative cost$$$$ High$$ Standard
Min. machined wall——
Best machined surface——

Pyrolytic Graphite vs RP Graphite Electrode — frequently asked

Is Pyrolytic Graphite stronger than RP Graphite Electrode?

Yes. Pyrolytic Graphite has a typical tensile strength of 100 MPa (14.5 ksi) against 7 MPa (1.02 ksi) for RP Graphite Electrode — about 14 times as much.

Which is cheaper, Pyrolytic Graphite or RP Graphite Electrode?

RP Graphite Electrode is the lower-cost material: it sits in the standard tier ($$) while Pyrolytic Graphite is high ($$$$). Part price depends far more on geometry, tolerance and quantity than on raw stock — upload a CAD file for a live quote.

Which is easier to machine, Pyrolytic Graphite or RP Graphite Electrode?

RP Graphite Electrode. Its machinability rates excellent (90/100) against good (55/100) for Pyrolytic Graphite.

Ready to make it?

Upload a CAD file and FabDigit prices the part in Pyrolytic Graphite and RP Graphite Electrode side by side — material, machining time, tolerance and finish in one quote. Certified material data ships with the order on request.

Typical handbook values for the conditions named above, normalised for comparison. Hardness on non-Brinell scales is converted approximately for charting only. Request certified data with your order for design-critical properties.