Tokai Carbon Europe Ltd.

Industries involved with processing molten liquids, in particular metals such as Iron, Aluminium, Copper and Precious metals and glass, use casting and metal treatment techniques that require the use of Graphite materials resistant to attack by the molten liquid. These Graphite materials must also not affect the final composition of the cast metal or deposit any hard particles in the melt that could cause problems during any subsequent post machining operations.
Continuous casting operations demand the use of Graphite for a number of reasons including:

1. A resistance to wetting by the molten metal
2. Efficient heat removal
3. Excellent thermal shock resistance

For processing aluminium alloys during such operations as degassing, Graphite shafts and rotors are ideal for the same reasons. Extended life is available with GRAPHOX treated Graphite. Tokai uses a post machining technique that ensures the Graphite parts are completely impregnated during the process.

There are many sectors of industry that use thermal processing in their production cycle. Many of these rely on furnaces that are electrically heated and hence need materials that have high thermal stability and high electrical loading capability. They also need to be resistant to aggressive media, thermal shock and be chemically pure so as not to deposit any unwanted elements during thermal processing. The use of Graphite parts offer the user the possibility to work at temperatures that are beyond the capability of metal and ceramic elements. These are usually not used above 2000ºC whereas graphite is capable of withstanding temperatures up to 3000ºC.

In the case of electrical steel production, graphite rolls are ideal for use in the decarburising or continuous annealing furnace. Traditionally materials such as steel or ceramics are used but graphite is becoming more favourable due to some of its unique properties. Graphite can withstand the aggressive atmosphere inside then furnace and has the unique property of getting stronger with higher temperatures. The property of lubricity means that the steel sheet is not scratched or marked as it passes over the roll on its way through the furnace.

Graphite is easily machined and so complex shapes can be made to suit the requirement of the furnace.

Tokai’s CC composite, Tokarec, has been developed as a high strength to weight ratio material suitable for many applications including carrier trays, structural parts and heater elements. The material has excellent shock and chemical resistance whilst having a low CTE and high purity.

The properties of Tokai’s Graphite’s and CC composite, Tokarec, makes them the ideal materials of choice for components used in furnace applications including Vacuum and Inert Atmosphere. Tokai Carbon’s extruded Graphite’s are consistent and properties are less dependant on grain orientation compared to other types.

The uses for Graphite have increased over the years and now many items that we encounter each day have, at some point, come into contact with Graphite products somewhere in the production life cycle.

The method of production determines the type of properties in the Graphite:

Isotropic Graphite are produced in a mould and pressed equally from all sides. In this case the properties are Isotropic-the same in all directions. These grades are high density, fine grain, strong and high hardness. Tokai produces HK grades for EDM applications and G grades for general applications.