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Heat Treatment - Tokai Carbon Europe

Heat Treatment

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 materials and grades recommended by Tokai Carbon for these applications are shown in the table below:

Vacuum Furnaces
Application Extruded/Moulded Graphite Isotropic Graphite Tokarec
Heating Elements FE250 G330 CC28NF
Furnace Furniture FE250 G347 CC28NF
Furnace Linings FE250
Boats FE250 G330
Sinter Trays FE250 G347 CC28NF
Crucibles G140 G348
Large Crucibles G140 G530
Electrical Steel Production
Application Extruded/Moulded Graphite Isotropic Graphite Tokarec
Conveyor Rolls FE250, FE250T G330, G330T
Carbon Fibre Production
Application Extruded/Moulded Graphite Isotropic Graphite Tokarec
Furnace Structure CC28NF
Heating Elements FE250