Machined Graphite

Machined Graphite Isostatically Pressed

What is Machined Graphite?

Our office provides custom machined graphite components for your specific application. Our engineering and manufacturing team can machine to print all sizes, complexities, shapes, and volumes of parts in the desired graphite grade in compliance with the requested tolerances as tight as +/- .003.” Machined graphite is used for heating elements, fasteners, hearth rails, connection blocks and nozzles, etc. The four primary types of machined graphite are: Extruded, Isostatically Pressed, Vibrated, and Molded. Additionally, the ash  and sulfur content of all grades can be halogen purified to < 30 PPM.

Types of Machined Graphite

Extruded Graphite– This grade of graphite is manufactured by pressing a fine graphite powder blended with pitch or another binder through a die under pressure. The resulting shape is then fired, impregnated, fired again, and graphitized at 2000℃. Extruded graphite grain size is approximately 10x larger than Isostatically Pressed Graphite, but it is more economical to produce. We carry Extruded Machined Graphite Rods such as JC4 Rods

Isostatically Pressed Graphite- Also known as Isographite or Isotropic Graphite is a grade of graphite manufactured by taking a fine grain graphite powder blend and placing it in a hot isostatic press. The completed pressed cylinder or block is then further heat treated to fully solidify, densify, modify, and purify the material to the final crystalline structure and properties desired. We carry Isostatically Pressed Machined Graphite Rods such as JC3 Rods

Vibrated Graphite – The most notable feature of vibrated graphite is the ability to produce larger requested sizes. The graphite is less dense then the other grades but is a perfect solution and cost effective when high strength is not required. It has an exceptionally homogeneous structure, almost isotropic properties, and low ash content.

Molded Graphite – This grade of graphite is similar to Isographite, but imported. It is manufactured by using a graphite powder mix and applying pressure in one direction. This type of production relies on the molded shape to hold pressure in comparison to Iso-static which applied pressure evenly in all directions. While this grade is not as isotropic in properties, it is the perfect solution when added cost and Isographite uniformity is not required. Typically, Molded Graphite is used for high volume applications and shapes such as washers.


  • Machinability to exceptionally close tolerances.
  • Good Thermal Conductivity as machined graphite is an excellent heat conductor and has great resistance to thermal shock.
  • High Compressive Strength ranging from 11K-38K lbs/in²
  • Corrosion Resistance for all practical purposes and is unaffected by most acids, alkalis, solvents, and similar chemicals.
  • Seal face flatness due to the high modulus of elasticity and stability to remain flat during operation at the rubbing faces.
  • Built-in Lubrications and Non-Galling. Products will not seize or gall in the most severe applications as the molecular structure of our machined graphite forms an extremely thin film on moving parts.
  • Porosity. Machined Graphite can be porous but impregnants are used to fill these pores and can range from high to totally impervious depending on need. Check out our GraphiSeal.
Graphite Blocks for Machining Vibrated Graphite


  • Electrodes and Semiconductors
  • Vacuum Furnaces and fixturing
  • Heaters and Heat shields
  • Electronic tube anodes
  • Continuous casting
  • Melting and sintering molds
  • Forge molds and EDM fixturing
  • Space and medical industry

Useful Charts.

Extruded Graphite Properties
PropertiesUnitEGK 1EGK 2EGK 3EGK 4EGK 5
Bulk Densityg/cc1.781.721.721.601.60
Max Grain Sizemm0.80.820.82
Ash ContentPPM30003000300030003000
Electrical Resistivityµ.Ω.m≤ 7≤ 8≤ 8≤ 8≤ 8.5
Flexural StrengthMPa1918171211
Compressive StrengthMPa4745443230
Isostatically Pressed Graphite Properties
Bulk Densityg/cc1.911.851.801.751.86
Ash Contentppm≤ 50500-1000500-1000500-1000≤ 500
Grain Sizeµm8-102525254-6
Specific ResistanceµΩm10-1211-1311-13≤ 15≤ 14
Compressive StrengthMPa138807555120
Flexural StrengthMPa6040372555
Shore HardnessRa6055505072
Coefficient of Thermal Expansion10-6 ℃
Young ModulousGpa1211.51010.512
Vibrated Graphite Properties
Bulk Densityg/cc1.721.711.601.58
Grain Sizemm0.8224
Specific Resistanceµ.Ω.m8.58.5910
Flexural StrengthMPa13.5137.87.5
Compressive StrengthMPa30282020
Coefficient of Thermal Expansion10-6/℃
Ash Content%
Molded Graphite Properties
Bulk Densityg/cm³1.781.85
Grain Sizeµm4343
Electrical Resistivityµ.Ω.m≤ 12≤ 12
Flexural StrengthMPa30-3535-45
Shore HardnessRa4045
Compressive StrengthMPa50-5560-82
Coefficient of Thermal Expansion10-6/℃2.52.5
Ash ContentPPM500-1000500-1000

Ready to order your custom Machined Graphite?

Please contact us directly to coordinate in regards to your custom quote and fabrication.