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Amorphous Graphite vs UHP Graphite Electrode

Ceramic · grade comparison

Amorphous Graphite and UHP Graphite Electrode are both ceramic grades. UHP Graphite Electrode is the stronger of the two: tensile strength 8 MPa (1.16 ksi) against 5 MPa (0.725 ksi) for Amorphous Graphite, about 60% more. In exchange, Amorphous Graphite is the more ductile: elongation 0.2% versus 0.18% for UHP Graphite Electrode. UHP Graphite Electrode is lighter (1.7 g/cm³ vs 2.25 g/cm³ for Amorphous Graphite) and UHP Graphite Electrode is stiffer (12 GPa vs 7 GPa). On the shop floor, Amorphous Graphite sits in a lower cost tier (budget, $) than UHP Graphite Electrode (standard, $$).

Amorphous GraphiteChoose it when the part is bent, formed or impact-loaded, or when cost is the deciding factor.

UHP Graphite ElectrodeChoose it when strength drives the design, or when weight is the constraint.

Amorphous Graphite vs UHP Graphite Electrode: properties

Amorphous GraphiteUHP Graphite Electrode

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

7 GPa1 Msi
12 GPa1.7 Msi

Tensile Strength (Ultimate)

5 MPa0.73 ksi
8 MPa1.2 ksi

Elongation at Break

0.2%
0.18%

Compressive Strength

30 MPa4.4 ksi
25 MPa3.6 ksi

Flexural Strength

9 MPa1.3 ksi
11 MPa1.6 ksi

Shear Strength

5 MPa0.73 ksi
7 MPa1 ksi

Fracture Toughness (K_IC)

0.8 MPa·√m0.73 ksi·√in
1 MPa·√m0.91 ksi·√in

Hardness, Vickers

15 HV
—

Hardness, Mohs

1.5
1

Poisson's Ratio

—
0.2

Physical

Density and transition temperatures.

Density

2.25 g/cm³0.08 lb/in³
1.7 g/cm³0.06 lb/in³

Porosity

—
23%

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

20 W/m·K11.6 BTU/hr·ft·°F
170 W/m·K98.2 BTU/hr·ft·°F

Thermal Expansion (CTE, 20–100 °C)

5.5 µm/m·K3.1 µin/in·°F
1 µm/m·K0.56 µin/in·°F

Max Service Temperature (continuous)

450°C842 °F
2,500°C4,532 °F

Same in both: Specific Heat Capacity 710 J/kg·K0.17 BTU/lb·°F · Min Service Temperature -200°C-328 °F

Electrical

Conductivity and insulation.

Electrical Resistivity

0.001 Ω·m39,370 µΩ·in
5.5×10⁻⁶ Ω·m217 µΩ·in

Volume Resistivity

0.1 Ω·cm
5.5×10⁻⁴ Ω·cm

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

85 / 100
75 / 100

Manufacturability

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

Sintering / Firing Temperature

—
2,900°C5,252 °F

Same in both: Machinability 90 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

15 MJ/kg6,449 BTU/lb
130 MJ/kg55,890 BTU/lb

Embodied Carbon (primary production)

1.2 kg CO₂/kg
6 kg CO₂/kg

Embodied Water

20 L/kg2.4 gal/lb
—

Same in both: Typical Recycled Content 0%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

2 kN·m/kg
5 kN·m/kg

Specific Stiffness (E / density)

3.1 MN·m/kg
7.1 MN·m/kg

Thermal Diffusivity

12.5 mm²/s
140.8 mm²/s

Thermal Shock Resistance Index

3
113

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

CapabilityAmorphous GraphiteUHP Graphite Electrode
Default condition——
Relative cost$ Budget$$ Standard
Min. machined wall——
Best machined surface——

Amorphous Graphite vs UHP Graphite Electrode — frequently asked

Is UHP Graphite Electrode stronger than Amorphous Graphite?

Yes. UHP Graphite Electrode has a typical tensile strength of 8 MPa (1.16 ksi) against 5 MPa (0.725 ksi) for Amorphous Graphite — about 60% more.

Which is cheaper, Amorphous Graphite or UHP Graphite Electrode?

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

When should I choose Amorphous Graphite over UHP Graphite Electrode?

Pick Amorphous Graphite when the part is bent, formed or impact-loaded, or when cost is the deciding factor. Pick UHP Graphite Electrode when strength drives the design, or when weight is the constraint.

Ready to make it?

Upload a CAD file and FabDigit prices the part in Amorphous Graphite and UHP 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.