Machinable graphite

Machinable graphite is known for its excellent isostatic qualities and its perfect homogeneity. It does not absorb moisture, deform, burst or shrink due to thermal stress.

Graphite offers optimal resistance at very high temperatures and in highly corrosive environments. Heat losses are minimalized and thermal conduction optimized. Graphite is self-lubricating and easily machinable.

Graphite, an essential material for the production of silicon, is widely used in the production of semiconductors. It is also an essential material for different dedicated machining solutions in the industries of plastic processing, glass manufacturing, metallurgy and even as an insulating material for furnaces.

Using scrap from our production of machinable graphite, we can also provide sifted powder in the following standard sizes.

Applications of machinable graphite

Graphite is used for the handling, machining and shaping of heated glass.

Machinable graphite is an indispensable material for the manufacture of tools for the transformation of heated glass.

Final offers a full range of materials and processes for the transformation of glass. With our extensive experience and know-how in this field, we are able to provide a full range of solutions for processes involving a number of metallic or composite tools using graphite.

Graphite machining

Graphite can be manufactured through extrusion or isostatic pressing.

  • HLM : Extruded graphite, standard particle size

  • HLR : HLM lower quality with higher porosity

  • R7340 : Isostatic standard

  • R7340P30 : Equivalent to R7340 with greater purity and an ash content less than 30 ppm

  • R4550 : Isostatic, fine particle size and very high mechanical strength.

  • R6650 : Isostatic, fine particle size and very high mechanical strength, exceeding those of R4550

  • R6650P5 : Equivalent to R6650, very high purity, ash content less than 5ppm.

  • R6710 : Isostatic, ultra-fine particle size and excellent mechanical strength

  • R6710P5 : Equivalent to R7340, very high purity, ash content less than 5 ppm suitable for semiconductor manufacturing.

After machining, isostatic graphite has a surface roughness of 0,6µm.

Technical data of machinable graphite

EXTRUSION

ISOSTATIC PRESSING

REFERENCES

HLM

R4550

R6650

R6710

R7340

Direction as per grain length

//

┴

// and ┴

// and ┴

// and ┴

// and┴

Density

g/cm3

1.7

1.83

1.84

1.88

1.72

Max. particle size

mm

0.8

0.01

0.007

0.003

0.015

Open porosity 

%

17

10

10

10

15

Electrical resistivity

Ohm.cm

7.3.10-4

9.4.10-4

13.10-4

14.10-4

13.10-4

12.10-4

Young’s modulus 

GPa

10

9

11.5

12.5

13.5

10.5

Flexural strength

MPa

18

17

60

65

85

45

Compressive strength

MPa

39

35

125

150

240

90

Tensile strength

MPa

13

12

/

/

/

/

Hardness

Shore 20-25

(Shore D 70)

Rockwell B

95

Rockwell B

95

Rockwell B 110

Rockwell B 80

Thermal expansion (20/200°C)

10-6.K-1

2.1

3.1

4

3.9

4.7

2.9

Thermal conductivity

W/m.K

180

140

100

90

100

90

Ash content

%

< 0.1

0.002

/

/

0.02

For the R7340 reference, we supply a wide range of bars directly extruded in a selection of standard diameters representing a significant cost-saving to the customer as the bars require no preparatory machining. These 300- mm. bars are available in the following diameters :

Ø 3.2 - Ø 4.8 - Ø 6.4 - Ø 7.9 - Ø 9.5 - Ø 12.7 - Ø 13.8 - Ø 16 - Ø 19 mm

Advantages of machinable graphite

  • They resist thermal shocks,
  • They do not adhere to glass,
  • They avoid mechanical tension in glass and prevent scratches on hot glass,
  • They feature low wear and friction coefficients, with positive thermal conductivity.

Our graphite-metal or graphite -composite tooling can increase the productivity of your production lines. They will make the set-up, settings and the maintenance of your production tools easier and quicker.

Blown glass

Final machines graphite moulds for glass casting and blow moulding.

  • Fixture and insertion mechanisms
  • Support plates, guides, handling mechanisms
  • Transfer wheels and rotary plates
  • Smelting crucibles
  • Press tools
  • Furnace insulation

Contact us

Machinable Graphite (211.99k)

Machinable Graphite Technical Data Sheet

Graphite (453.67k)

Technical data sheet Graphite.

FAQs that can help you in this category

Can graphite resist to the same temperatures when in air, in a vacuum or in an inert atmosphere?

Graphite can withstand different temperatures depending on the atmosphere in which it is used. Its working environment directly affects its thermal performances.

In a vacuum or an inert atmosphere, graphite can withstand extremely high temperatures, even above 2,000°C. If oxygen is not present, the material retains excellent thermal and structural stability.

In air or an oxidising atmosphere, however, the maximum working temperature is lower. At around 400 to 500°C and above; graphite starts to oxidise gradually on contact with oxygen, leading to a degradation of its properties and loss of material.

Choosing the right graphite grade and considering the atmospheric conditions in which the graphite will be used is absolutely necessary to obtain the performance and lifetime needed for a given application.

The Final Advanced Materials team is at your disposal to help you choose the most suitable graphite solution based on your thermal and environmental constraints.

Is graphite an electrical and heat conductor?

Due to its layered crystalline structure, graphite has excellent electrical and thermal conductivity properties.

This organisation facilitates the movement of electrons and the propagation of heat within the material.

However, graphite also has anisotropic properties: its conductivity varies depending on the direction of the crystalline layers. Conductivity is thus higher in the direction parallel to the layers than in the direction perpendicular to them.

Parameters such as the graphite's purity and density also influence its electrical and thermal characteristics. All these characteristics therefore determine the level of conductivity of the material.

Despite these variations graphite remains an excellent thermal and electrical conductor, which is particularly suited to many demanding industrial environments.

The Final Advanced Materials team is at your disposal to help you choose the most suitable graphite for your technical requirements.

Is graphite suited for aggressive chemical environments?

Graphite is an excellent solution for aggressive chemical environments.

Due to its great chemical stability, it resists most acids and bases, including at high concentrations.

Unlike metals, graphite does not rust and does not dissolve in most corrosive environments, making it a material which is particularly suitable for demanding applications.

However, there are certain limitations which be taken into account. In the presence of oxygen and high temperature, graphite is subject to oxidisation which can impair its properties. In addition, in fluorinated environments, in particular in the presence of hydrofluoric acid, a direct chemical reaction with carbon can occur.

The choice of graphite and working conditions therefore depends on the application's chemical and thermal environment.

The Final Advanced Materials team is at your disposal to help you choose the best graphite for your technical requirements.

Can I use a graphite-loaded cement to repair graphite parts?

A graphite-loaded cement is a particularly suitable solution for repairing graphite parts.

Its chemical compatibility with the material, along with its thermal expansion and electrical conductivity, which are similar to those of graphite, make it a preferred solution for this type of application.

Ceramic-loaded cements are particularly recommended for localised repairs which do not require high a mechanical strength.

The Final Advanced Materials team is at your disposal to help you choose the best solution for your technical constraints.

Does graphite have lubricating properties?

Graphite naturally possesses lubricating properties which is one of its most widely acknowledged characteristics.

Due to its layered structure, where the different layers easily slide over one another, it is an excellent solid lubricant.

However, its performance can vary depending on the working environment. In an inert atmosphere or in a vacuum, its effectiveness diminishes due to the scarcity of gas and moisture, elements which make it easier for the graphite layers to slide over one another.

However, in an oxidising, high-temperature atmosphere the main challenge is its natural oxidisation, which can impair the graphite’s properties.

The choice of graphite therefore depends directly on the working conditions and on the constraints specific to your application.

The Final Advanced Materials team is at your disposal to help you select the graphite solution which is most effective and best suited to your needs.