The correct selection of the material quality is essential for a good service life and, therefore, for the cost effectiveness of a chain system. Kiln temperature, kiln gases and type of firing are the primary components in the selection of material qualities.
In the first kiln sections, where the gas temperature is usually below 500°C, carbon steels can be installed. If mechanical wear is higher, low alloy steels are recommended which may also be heat treated for lower wear.
Compared with carbon steels, low alloy steels have a higher core hadness and will give better service in temperature ranges between 300 up to 500°C
Ferritic steels are very resistant to sulphurous gases, but less suitable for nitriding and/or carburizing atmospheres.
Austenitic Cr-Ni steels are more resistant to carburizing atmospheres, but unsuitable for sulphurous gases.
Cr-Ni-Mn steels combine the advantages of ferritic and austenitic alloys and are especially suitable in kilns with sulphur containing gases with carburizing conditions. A well designed liln chain system can consists of austenic manganese and ferretic steels if the kiln is fired with pet coke, coke and waste if the risk of caburizing is small. For high caburising atmospheres only austenitic manganese qualities should be installed.