Machined Graphite



Machined Graphite from CeraMaterials

What is Machined Graphite?

Our office provides custom fabrication and machining of solid graphite for your specific application. Our engineering and manufacturing team can machine to print all sizes, complexities, and volumes of parts in the desired graphite type in compliance with the requested tolerances. The four primary types are Extruded, Isostatically Pressed, Vibrated, and Molded. Additionally, the Ash content of all grades can be purified to 50 PPM.

Types of 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 then Isostatically Pressed Graphite, but it is more economical to produce.

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.

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 mold 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, it is used for high volume applications and shapes such as washers.

Benefits

  • Machinability to exceptionally close tolerances.
  • Good Thermal Conductivity as 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 graphite forms an extremely thin film on moving parts.
  • Porosity. 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 from CeraMaterials

Applications

  • 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
PropertiesUnitsIFS-1IFS-2IFS-3IFS-4IFS-5
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 ℃
54.54.44.04
Young ModulousGpa1211.51010.512
Vibrated Graphite Properties
PropertiesUnitsVSK-1VSK-2VSK-3VSK-4
Bulk Densityg/cc1.721.711.601.58
Grain Sizemm0.8224
Specific Resistanceµ.Ω.m8.58.5910
Flexural Strength MPa13.5137.87.5
Compressive StrengthMPa30282020
Coefficient of Thermal Expansion10-6/℃2.52.52.32.3
Ash Content%0.30.30.30.3
Molded Graphite Properties
PropertiesUnitsM1M2
Bulk Densityg/cm³1.781.85
Grain Sizeµm4343
Electrical Resistivityµ.Ω.m≤ 12≤ 12
Flexural Strength MPa30-3535-45
Shore HardnessRa4045
Compressive StrengthMPa50-5560-82
Coefficient of Thermal Expansion10-6/℃2.52.5
Ash ContentPPM500-1000500-1000

Ready to Order?

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

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